Lifthrasil: Actually I prefer semi-open games. How the roles work should be known. But not necessarily which roles are present in the game. Some quirks can be left as surprise, if necessary for the setting, but completely closed games are too random because players can't plan at all. So it's better if the mechanics are known.
On the whole I agree. Unless it's known to be a bastard mod game in advance, a design that has both sides pursuing counter-productive strategies (while amusing) is generally not going to end well unless you've carefully balanced it.
I do like the AAC concept quite a bit though, I think it opens the door to some really interesting claiming gambits, as well as some tough decisions for all factions as to what to do. And it takes some of the paranoia out of the standard role.
The DNA cop is interesting, but if you are seriously thinking that the role would pick up multiple DNA results, it should arguably pick up anyone active, not just them killers then. But if I'm following you I think the codebreaking part is a bad idea, unless you're implying the mod is doing that work.
Also, semi-useless cops aren't the worst thing in the world, as long as the overall setup is balanced around that. In some ways it's easier to plan a game around 2 weak cops than 1 strong cop, which can be super swingy if it dies early or gets a hit early. Adding a N0 action can help counteract some of that weakness as well.
Similar to Wyrm's point/question, would all pools be announced to all players in advance, or is each player picking from their pool knowing nothing about the rest of the setup? I think the picking potentially becomes problematic if it's secret, but a bit weird potentially if open.
More importantly, with those examples you could end up with a completely unbalanced game if say, town picks three cops and a tracker, and maf picks BP + strongman (i.e. functionally no roles at all), which may just not be that much fun to play.