I meant to include a brief summary of the changes, but for some reason the message didn’t go through, so I’m writing it now:

MONK

Monk has been changed A LOT, from disengaging being free (you only spend Ki points to add Dash/Dodge to the same disengage bonus action), to being able to replenish Ki on initiative once per long rest, to Deflect now working on all melee and ranged physical attacks (and later upgraded to spells as well). It also retains the UA5 martial art die progression (d6 to d12 instead of d4 to d10 as it was in 2014).

It’s in a far better position than it was in 2014 and in UA5. It is worth mentioning, however, that Stunning Strike has been nerfed to once per turn (instead of once per hit as in 2014), making the class overall goal shift from the stunning dispenser that it was in 2014 to a glass cannon DPS build (which can attain ungodly amounts of AC with time, especially with the new capstone).

BARBARIAN

Mostly the same as the last UA, with a few changes here and there. Most notably, Brutal Critical has been replaced by a new feature, that lets the barbarian attacking with Reckless Attack forfeit the advantage on the first attack to add an additional damage die and an additional effect, including Push or disadvantage on the next saving throws the target makes. The video released on the official DnD channel confirms that this is meant to work in tandem with the weapon masteries.

It’s unclear what this means for optimization: from a mathematical perspective, it seems that attacking with advantage will lead to higher DPS overall, and the gap widens if magic items are taken into account. It seems that the designers meant the barbarians to choose between higher damage output and situational effects, kind of like the rogue is now able to trade sneak attack damage for their weapon arts.

DRUID

They decided not to go the stat block route for Wildshape, instead asking the players to “prepare” stat blocks from the monster manual as if they were spells, gaining more forms over time. I respect their decision, but it kills my interest in this class, so I didn’t bother with giving it anything more than a cursory glance.

SPELLS

Healing spells were buffed (Cure Wounds now gives 2d8 HP instead of 1d8, Healing Word 2d4 instead of 1d4, etc). Problematic conjuring spells like Conjure Woodland Beings and Conjure animals were nerfed, and don’t summon a bunch of critters anymore. There are some new spells as well, including Power Word Fortify, a 7th level Power Word that distributes 120 Temp HP in equal measure to up to six creatures, and Starry Wisp, a bard/druid cantrip that deals 1d8 radiant damage and makes the target glow.

Other spells are included in the playtest, including Conjure Celestial, Conjure Elemental/Minor Elemental, and the new Fount of Moonlight. I won’t discuss each and every one of them, as this post is mostly meant as a summary of the overall changes, but you can click the link and read it for yourselves.

OTHER CHANGES

Since the OneDnD playtest is almost over, it’s worth mentioning some of the other changes that were introduced in previous UAs that are still here and are probably meant to stay:

Invisibility grants advantage on initiative rolls; Nets are part of the adventuring gear, and are not weapons anymore; the new Dazed condition; Hide giving you the Invisible condition; Animal Handling being (apparently?) grouped with other Charisma skills, like Deception and Persuasion.

On a side note, Exhausted rules from the earliest UAs, which consisted of a (stacking) -1 malus to d20 rolls and spell save DC in place of the far more deadlier 2014 Exhaustion rules, are still nowhere to be found. I hope they’ll at least sneak them into the DMG as an optional rule instead of discarding them completely, as I think they are far better than the previous exhaustion rules.