Hello, yes, I am interested.

Getting right into the discussion at hand, I'd prefer the former idea. Mostly because I'm a bit on the "that guy" side of things in enjoying more obscure character concepts. The prophecy to drive the story, which you mentioned, can be written retroactively to suit the character base, and incorporate elements other than character class, such as region of origin, which you mentioned.

Just something that crossed my mind: presenting various options or roles to players, and then asking that each selection be unique between characters breeds something akin to competition within a game. Things tend to dissolve into a contest of who can grab what first, and the other players are left trying to work a character into whatever it is that remains. Perhaps we, the prospective players, can put forth character concepts, and our general input could be used to shape the setting to an extent? Just a thought to ease the character creation process.