Yochlol redone as Arachnoloth

The yochlols arachnoloths are the Handmaidens of Lolth--extensions of the Spider Queen's will dedicated to acting as her spies, taskmasters, and agents of villainy.

It is believed that Lolth possesses one of the Books of Keeping containing the true names of all of the yochlols--renamed arachnoloths by Lolth and her drow worshipers--which might explain why these yugoloths, normally notorious for their shifting loyalties, serve Lolth unswervingly.

YOCHLOL ARACHNOLOTH
Medium fiend (demon yugoloth, shapechanger), chaotic neutral evil
Armor Class 15 (natural armor)
Hit Points 136 (16d8 + 64)
Speed 30ft., climb 30ft., fly 30ft.
STR 15 (+2)
DEX 14 (+2)
CON 18 (+4)
INT 13 (+1)
WIS 15 (+2)
CHA 15 (+2)
Saving Throws Dex +6, lnt +5, Wis +6, Cha +6
Skills Deception +10, Insight +6
Damage Resistances cold, fire, lightning; bludgeoning, piercing, and slashing from nonmagical weapons
Damage Immunities acid, poison
Condition Immunities poisoned
Senses blindsight 60ft., darkvision 120ft., passive Perception 12
Languages Abyssal, Infernal, Elvish Sylvan [Elvish does not exist in my world], Undercommon, telepathy 60ft.
Challenge 10 (5,900 XP)

Shapechanger. The yochlol arachnoloth can use its action to polymorph into a form that resembles a female drow or giant spider, or back into its true form . Its statistics are the same in each form.  Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Magic Resistance. The yochlol arachnoloth has advantage on saving throws against spells and other magical effects.

Spider Climb. The yochlol arachnoloth can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Spider Affinity.  Arachnoloths have a special kinship with spiders.  Even untrained spiders recognize arachnoloths as allies and don't prey on them.

Spider Telepathy.  Arachnoloths can magically command any spider of CR2 or less that is within 120 feet of it, using a limited telepathy.

Innate Spellcasting. The yochlol's arachnoloth's spellcasting ability is Charisma (spell save DC 14). The yochlol arachnoloth can innately cast the following spells, requiring no material components:
At will: detect thoughts, web
1/day: dominate person

Web Walker. The yochlol arachnoloth ignores movement restrictions caused by webbing.

Magic Weapons. The arachnoloth's weapon attacks are magical.

ACTIONS
Multiattack. The yochlol arachnoloth makes two melee attacks.

Slam (Bite in Spider Form). Melee Weapon Attack: +6 to hit, reach 5 ft. (10ft. in demon form}, one target. Hit: 5 (1d6 + 2) bludgeoning (piercing in spider form) damage plus 21 (6d6) poison damage.

Mist Form. The yochlol arachnoloth transforms into toxic mist or reverts to its true form. Any equipment it is wearing or carrying is also transformed. It reverts to its true form if it dies.
While in mist form, the yochlol arachnoloth is incapacitated and can't speak. It has a flying speed of 30 feet, can hover, and can pass through any space that isn't airtight. It has advantage on Strength, Dexterity, and Constitution saving throws, and it is immune to nonmagical damage.
While in mist form, the yochlol arachnoloth can enter a creature's space and stop there. Each time that creature starts its turn with the yochlol arachnoloth in its space, the creature must succeed on a DC 14 Constitution saving throw or be poisoned until the start of its next turn. While poisoned in this way, the target is incapacitated.

Teleport. The arachnoloth magically teleports, along with any equipment it is wearing or carrying, up to 60 feet to an unoccupied space it can see.

A Nice Combo: Durable + Wound Closure

Durable feat
When you roll a Hit Die to regain hit points, the minimum number of hit points you regain from the roll equals twice your Constitution modifier (minimum of 2).

Periapt of Wound Closure
Whenever you roll a Hit Die to regain hit points, double the number of hit points it restores.

5e Giants and Empyreans

Here is how I would modify giants and empyreans:

Hill Giant

Hill giants are removed from my game.  Here is why:

i) I adopt a 4th edition approach to giants, as creatures originating from the Elemental Chaos.  Hill giants appear as nothing more than enormous, natural humanoids.  The other giants appearing in the 5e Monster Manual have more obvious ties to elemental origins.

ii) Hill giants are too similar to ogres.  Ogres have STR 19, INT 5 and wield greatclubs.  Hill giants have STR 21, INT 5 and wield greatclubs.  They both look like large, ugly humans (admittedly, fifth edition has made ogres even uglier), and only 3 challenge levels separate them, despite one being large and the other being huge.  By removing hill giants, the leap from ogres to giants is 5 challenge levels (2 to 7).

I would have ogres occasionally referred to as hill giants, as a misnomer, of course.  Ettins are born of ogres with the frequency of twins.

Stone Giant

Stone giants are hairless.

Senses darkvision 60ft., tremorsense 60ft., passive Perception 14

Damage Resistances: bludgeoning, piercing, and slashing damage from nonmagical weapons.

At will: Mending (stones and minerals only)
1/day each: Meld Into Stone, Stone Shape

Frost Giant

Their hair resembles frost.

1/day: Fire Shield (chill shield)

Greataxe (Hit: 25 (3d12 + 6) slashing damage plus 5 cold damage).

Rock (Hit: 28 (4d10 + 6) bludgeoning damage plus 5 cold damage).

Fire Giant

Their hair resembles embers.

1/day: Fire Shield (warm shield)

Greatsword (Hit: 28 (6d6 + 7) slashing damage plus 5 fire damage).

Rock (Hit: 29 (4d10 + 7) bludgeoning damage plus 5 fire damage).

Cloud Giant

Their skin is pearly white.  Their hair resembles cloudstuff.

At will: Feather Fall, Fog Cloud, Levitation
3/day each: Fly, Misty Step, Telekinesis
1/day each: Control Weather, Gaseous Form

Morningstar (Hit: 21 (3d8 + 8) piercing damage plus 5 thunder damage).

Storm Giant

I want to align storm giants closer to the water element, so as to provide a greater distinction from cloud giants (air element).  Storm giants have a deep sea green pigment.  Their hair resembles seaweed.  They live in or near oceans or enormous lakes.

At will: Create or Destroy Water, Water Walk
3/day each: Control Water, Tsunami, Water Breathing

Instead of a greatsword (Hit: 30 (6d6 + 9) slashing damage), a storm giants wields a trident (Hit: 20 (3d6 +9 or 23 (3d8 +9) if used with two hands to make a melee attack piercing damage plus 10 lightning damage).

Empyrean

At will: Create Food and Water, Greater Restoration
3/day each: Aura of Life, Aura of Purity
1/day each: Commune, Dispel Evil and Good, Divine Word, Plane Shift (self only), Raise Dead

Bolt (Hit: 24 (7d6) radiant damage).  This damage ignores resistance to radiant damage.

Druidcraft, Prestidigitation, and Thaumaturgy

These cantrips represent the most preliminary form of magic.  Any class that has any of these cantrips on their spell list as a first character level should get it as a bonus cantrip.  Note, however, that obtaining these cantrips via a feat or some other means does not qualify.

5e Racial Weapon Proficiencies and Exotic Armor

Some of my 5e changes:

Racial Weapon Proficiencies:

Dwarf

Dwarf Combat Training should replace the battleaxe and handaxe with the war pick. Dwarves are miners and smiths, not lumberjacks. Therefore, many dwarves naturally would have experience with hammers and picks, but not axes.

Elf

Elves favor weapons that exploit their superior dexterity (i.e., finesse weapons).

For High Elves, Elf Weapon Training should be renamed High Elf Weapon Training, and it should replace the longsword and shortsword with the rapier. High Elf fighters tend to be Eldritch Knights with the Dueling fighting style, so as to leave one hand free for spellcasting. High Elf rogues tend to be Arcane Tricksters.

For Wood Elves, Elf Weapon Training should be renamed Wood Elf Weapon Training, and it should replace the longsword and shortsword with the scimitar.

Drow Weapon Training should remove rapiers.

Half-Orc

Half Orcs should receive Orc Combat Training, which grants proficiency with the battleaxe and greataxe.

Exotic Armor:

Wood elves make exotic armors composed of (i) specially treated leaves (effectively leather armor), and (ii) a combination of specially treated leaves and specially treated bark (effectively studded leather armor). These armors generally are made in wood elven communities for use by wood elves, exclusively.  Wood elves do not teach this technique to other races.

Thoughts on Giants and Titans

I am looking forward to D&D Next. I notice that, in many respects, D&D is shifting back to its pre-4e concepts. In many respects, I welcome this return. In other respects, I lament it. I rather enjoy 4e's take on D&D cosmology. With the Nine Hells existing within the Astral Sea, and the Abyss existing within the Elemental Chaos, everything makes more sense to me than the Great Wheel. Another aspect to 4e that I embraced was the classification of giants and titans as elemental creatures--I would go further and classify dragons as elemental creatures. I wish that would remain so in D&D Next. There are a few changes that I would make to giants and titans: (i) giants and titans would be regrouped as follows: (A) Frost Giants and Ice Titans; (B) Earth Giants and Stone Titans; (C) Ember Giants and Fire Titans; (D) Cloud Giants and Storm Titans; (ii) some giants would be re-imaged, with their element most evident in--or as--their hair: (A) Frost Giants resemble the Frost Giants of old; (B) Ember Giants resemble the Fire Giants of old; (C) Earth Giants would not resemble the Hill Giants of old. Instead, they would show more evidence of their earthy substance, somewhat like the 4e Earth Titan; (D) Cloud Giants would resemble the Storm Giants of old; (iii) all titans would be re-imaged: (A) all titans would look much more like their elemental substance, standing midway between primordials and giants, not simply in size and but also in appearance. In other words, titans are not simply larger looking giants; (B) titans, being far more powerful than giants, eschew the use of manufactured weapons. All titans have a slam attack; Note: Ogres would resemble the Hill Giants of old, and often are called Hill Giants, which is a misnomer because ogres certainly are not giants. Giants are elemental creatures, whereas ogres are natural creatures. Also, ogres are not as powerful as Earth Giants, the least of all giantkind.

proposed multiclass feat system

i wonder whether this method might be more effective . . .

I. one multiclass feat to rule them all:

i) choose one of any class skill;
ii) ability to use all class weapons or implements;
iii) access to any class feat; and
iv) access to any class paragon path and epic destiny.

II. one class powers feat:

i) ability to use one encounter, daily AND utility power of the class; and
ii) prerequisite of the multiclass feat.

III. one class features/powers feat:

i) choose one class feature;
ii) ability to use one at-will power, and a second encounter, daily AND utility power of the class; and
ii) prerequisite of the class powers feat.