Out of curiosity, would it be possible to use the Drain Resources ability as an assimilation weapon that can be fired at ships? I tried it and got a minidump, but I might've been doing something wrong because I'm not terribly smart. But if it could be made to work, it would make for some very different and more in-character Borg. Assimilating ships by just taking them over isn't their MO.
But imagine (and I know this will probably never work) if you set the Borg up like this:
They get one ship--a capital ship cube. They can't colonize worlds or build asteroid mines. Their entire economy is based on draining resources from enemy ships (all of their weapons would have this effect). In the early game they'd get by assimilating planetary defenders, and later they'd gain resources in combat with other players.
Three things would keep them from rushing and killing everyone in the early game: first, the cube would have to level up before it poses a serious threat to a player fleet. Second, their high hull regeneration rate could be an in-culture bonus (call it the collective), so they'd be much more vulnerable in hostile or neutral territory. And third, with only one ship (at least in the early game - their fleet caps could be manipulated to allow a second cube to be built later on if you collect enough resources) an attack on another player's empire would leave their homeworld virtually unprotected.
Anyway, I'm having a blast with the mod even in it's unstable and unbalanced state, so keep up the good work.