I looked at it and my first impression was that artificers getz MOAR AC? ;-)
Not sure that was necessary, especially along with the temp hp benefit. Temp hp is what's really good about artillerists and the
heroism spell. I do like the magically powered power armor concept though.
You learn how to use your artificer infusions to specially modify the armor enhanced by your Power Armor feature. That armor now counts as separate items for the purposes of your Infuse Items feature: armor (the chest piece), boots, bracers, and a weapon. Each of those items can bear one of your infusions. In addition, the maximum number of items you can infuse at once increases by 2, but those extra items must be part of your power armor.
There was some confusion on this earlier. The armorer subclass does increase the total number of items infused. These extra two just can't be handed out like others can.
I think 2 extra infusions is pretty good.
The druid should have wildshapes based on constellations. I saw that earlier and agree.
The ranger is interesting. It looks like the psychic damage is more applicable to multiple targets instead of concentrating damage on one target. I like the flavor, not sure if it's good mechanically or not just looking at it.
I am curious as to how it plays along with the UA for alternative features that gives rangers a lot more spells already. More spells via alt class abilities plus free spells known via subclass seems to give a lot to rangers. We're up to rangers knowing as many spells as lore bards at that point.
A bard ends up with 22 spells known. With both UA's the ranger ends up with 24 spells known. The bard also has 22 spells slots. The ranger has 15 spell slots plus 7 free castings of primal awareness spells plus the free castings of
hunter's mark for up to 5 more castings (concentration free). We actually have rangers casting more spells per day than most classes.
That strikes me as a bit odd with better weapons, better hit points, better armor, additional damage abilities, another skill from cunning will, and adding wisdom modifier on top of charisma for charisma checks (likely simply using WIS double duty). Running out of reasons to play a warlock kind of fast there. ;-)