In addition to the Barbarian, Druid and Monk, the playtest packet includes changes to a number of spells.
The largest number of changes are to conjure spells. I think it's a bit odd that the summoned entities can't be interacted with by attacks or most spells, but otherwise I generally like these spells. I do think that they're sufficiently different from the 2014 spells that they should be considered new spells with new names. I assume the intent is to avoid having other books reference spells that don't exist in the 2014 rules, but having these books reference a spell that's completely different from the one they originally intended to reference seems like just as much of a problem (especially when a different set of spells is filling the role of the original conjure spells).
I'm not sure what to think of the changes to cure wounds and healing word yet. This is definitely a significant buff to spells that were already widely used, albeit not as significant as the raw numbers imply (since bringing a target back from unconsciousness is often more important that the numerical amount of healing). This should make in-combat healing of conscious targets more attractive, but magical out of combat healing will also be dramatically improved. All in all, this will allow players who enjoy a healing role to be more effective, but I worry it will also increase pressure for players who would rather do something else to take on a healing role.
Power Word Fortify and Starry Wisp seem like elegant additions to the game. I particularly like that Starry Wisp gives Bards an alternative to Vicious Mockery as an attack cantrip.
Of course, what's also significant are the spells not included in the playtest. I was very glad to see the balance pass on cantrips in the Bastions UA, and I think the leveled spells would benefit from a similar treatment. Hopefully this is at least happening through the internal playtest, since it seems like time's run out to include this in the public playtest.