Well also, since bomber would appear as villager to mafia, and bomber would not share a meeting with the mafia, there is no way the bomber could coordinate with mafia. Therefor the bomber could also kill a mafia with the minority vote.
Then it is essentially a mafia-sided hunter, only instead of picking who they kill after they're lynched, it's while they're being lynched. The only difference is that if there are enough villagers, they can force a minority vote on someone less important, I.E. if you know who the cop is, and they pick the blues, then you can't, but it's still really just a maf-hunter, which isn't bad. It could be used in roles where people ask the hunter to claim for a clear, and the bomber can just CC the hunter... I guess.