I think DM needs a bigger variety of weapons, so the two I think which could work well are the Panic Attack and the Tomislav. The tomislav would be a more lightweight version of the minigun with stats like they are in the original game, and I think that would be more fun to fight both with and against than the minigun. The panic attack (in the state before the buff in the Jungle Update where you have to load the shells before you fire them all at once) would be very fun in Deathmatch because of its principle. You could peek around corners and drop people, but if someone catches you off guard you would be screwed for a few seconds if you don't have a reliable secondary. I think it could be fun, maybe with a little balancing, though.