Saracenus
Always In School Gamer
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.
Actually, the Themes are centered on Neverwinter and not the entire Forgotten Realms so some place specific material is expected and desirable. These are not generic Themes like we got in the eDragon (I liked them too, but by their very nature don't have a ton of background flavor).
If you look at a few, the are not specifically for Essentials because several mention classes outside the Essentials, I remember Bards specifically.
Here is the other thing, if you don't like a restriction and can justify a change, make a change.
My Two Coppers,