As a mature player: I would like to have "mature" themes, but not them being presented to me, just for the sake of stuff being "dark" and "gritty".... but just one aspect of the gameworld.
As a gamedesigner being concerned with mass-appeal: I would make any mature themes only "implicit". So that rating agencies won't ban my game just because it contains SOME mature themes (i do not think current rating agencies could deal with optional mature themes at all, unless it was heavily stupidified down).
As an egoistic mature player: I would like ED to have mature themes in a way, so that it bores people just going for the "wow!", yet alienates teenies, so that the audience playing ED is more biased towards a spectrum of players i can relate with (see, *i said* "egoistic")