My initial feeling is that it certainly feels adequate. Not so small that I'm really wishing for more, but nothing that makes me go "
holy shit, this is absolutely enormous". Portaling or loading between zones always adds to the compartmentalized feeling of some games (this was very evident to me in SWToR), and I get a little tiny bit of that same feeling here, though not nearly as bad.
I really can't pass full judgement however, as I only attended one BWE, and there's much I didn't see.
For the record, WoW doesn't feel all that huge to me either (ex AC player), so...