Hmm. If I'm playing something wacky, like a Dragonborn Battlemind or something, it seems my only options for Neverwinter themes are Harper Agent, Devil's Pawn, Oghma's Faithful, and Spellscarred Harbinger. 4 options isn't terrible, but still, I feel like they may've gone overboard with the restrictions.
Renegade Red Wizard is very disappointing for me, personally. How many mages are actually going to use that ability? When was the last time you saw a wizard (successfully) go hidden without invisibility involved? Also, I'm not sure why they decided to restrict it strictly to Mages, when Arcanists seem to fit the flavor just fine. I can only guess that [tin foil hat] this is Wizards continuing the "play Essentials please, nothing to see in the original PHB, continue along" tactic [/tin foil hat].
I kind of like the one that lets you turn into a wolf. It's not clear, though, if you can still use powers in your wolf form. Could a Slayer or Thief use that Bite as a melee basic and still pull off all their crazy damage stuff? Could be a fun character.
Oghma's Faithful strikes me as a little useless, since their Encounter power has almost no combat utility. There's nothing inherently wrong with that, but when literally every other Theme out there is focused around some aspect of combat, well... it just doesn't stack up. Also, Encounter powers that should be Dailies are a pet peeve of mine. Why is this an Encounter power? Are you really going to be running into an unfamiliar language every five minutes? In my opinion, this should be a Daily power, and then this Theme should get a little something extra to help its combat ability.
Scion of Shadow made me chuckle. Oh, I can play a Shade with the DM's permission? That's good, because you just know everybody's going to be begging to play a Shade... I do kind of like the Daily power, though.
Spellplague Harbinger strikes me as the most powerful. Turning invisible as a minor action is useful and powerful for literally any class.
Yay themes, though. I love themes. Always good to see new ones, and these ones (with the exception of Oghma and the Red Wizard) are pretty good!