Mammets are a good disrupter honestly there is a possible strat with Cruisers, since you can only have 2 Opps and 2 Brutes max, in theory you could have cruisers protecting the mammets while the players next to the cruisers kill the enemies mammets. Since the player has to be in a specific location to attack your mammets it would be easy to swipe kill them with Cruisers.

Just a theory though I haven't seen it done.

Also, Mid isn't to OP it's just when you don't get mid you need to adapt your strategy, Tanks give you +10 and killing mammets get you some CE, if players just keep in mind the situation they are in they can adapt to it.