TwoSix
Everyone's literal second-favorite poster
To my mind, the single biggest difference between TSR D&D and WotC D&D is that in the older versions, you created characters, but in the newer versions, you built them.Yep, this is the real question: what is the difference between a Class and a Theme? Right now we have the Cleric of Moradin, who looks a lot like the Paladin class for all intent and purpose. Give him a Lay on Hands ability at 4th level and a special mount at 6th, and you've got a very serviceable paladin.
Themes (which are really parcels of feats) seem to reflect this difference, being something that you can make choices on as you level. The point of pre-packaging feats into Themes seems to be to turn a character-building option into a character-creating one, which seems to be more palatable to a larger section of the player base. After all, even Pathfinder's mechanical upgrade was granting more creation options to all the character classes, via alternate class features.
The question to my mind is, will 5e have any more character building options that feats? And if so, are they going to be embedded into classes, or into another subsystem altogether?