If they keep up girls: Darry and/or Kittan's harem
If not: Simon, Viral, Kamina, Viral, Kittan or Leeron (just kidding about the last one)
If not not: The Mecha
For all you saying they won't release another one/they won't release any male themed ones, remember we're talking about Gainax, if they haven't finished milking Eva (haha, obviously not what with the movie remakes of the show) they certainly haven't finished milking GL, in fact they're just starting I mean, it hasn't been a decade and they're releasing movie versions of the series (though these should go a different path, thus not being complete remakes, kind like the Eva movies. Hmm...).