For me, A mod that gets the right balance between survival/Realism at the same time having a good PVP/PVE aspect , for example, some of the A3 milsim type game-play wouldn't fit in because its not really accessible to the casual player, looks great, but not really a pick up and play 'thing'.
I played Overwatch then Epoch and then Overpoch for a good year or so with various different groups, probably the best A2 mods Ive played.
Did have a play around on exile the other day ( literally 2/3 hours ) so I don't think I've really given it a chance. Kind of a huge TWD fanboy so the lack of zombies or any other PvE aspect kind of puts a downer on it,feels a bit too 'wastelandy', another pet hate is no night cycle, A3's lighting system is cool, the use of floodlights/NVGs/ general stealth play adds so much ( Ive said this a million times before) yet barely any servers enforce a night cycle.
Ive yet to try BP looks as though it lacks any progression or endgame for example base building. Kind of gone offtopic there, if there is any groups around playing exile give me a shout, although its a PITA I don't mind having to download multiple mods.