I agree, Deena just isn't that interesting of a character.
And perhaps, it was originally more Deena focused, but I think it would have made a lesser show. Who can say, though.
I'm not sure how much you can beef up a not that interesting part, and still let Hudson sings two show stoppers, while Deena has... Dreamgirls, Heavy (kind of), the Dreams Medley (Opening of Act II), One Night Only, and it's Hard to Say Goodbye.
God knows all of those songs won't be there. And even if they were, they're big numbers that feature 3, or are about Deena NOT being Effie, or Deena replacing Effie, etc.
I know Beyonce will get a big solo number, but I'm ALWAYS suspicious of added songs. They're never as good.
Poor Anika, though. She's the one I feel bad about. She doesn't even have Ain't No Party anymore?
That's my third favorite number in the show, and I think the second best role in the piece.
Personally, I think I have too much bloom.