...or making the custom characters actually in any way customizable so that they don't feel like a blank slate with no unique interactions with the world are speaking for themselves...
Not to sound melodramatic, but this is a real concern for me. When I 'buy in' to an RPG, I want to be in world as my character -- not someone else's. As you say, truly custom characters do seem to be lacking when compared to the origin characters. And from what I've read on these forums, some plot lines and NPCs don't truly light up until you play as an origin - Durge, in particular - and that feels like a real problem to me.
(Oh, and I still haven't finished Act 3. Probably never will at this rate.)
