Idea works fine in principle, but every single match I've gone into so far has just been the opponent spamming skip grenades over and over again.
By the time you've recovered from the barrage of tiny blue clusters of -blam!-, the opponents have heavy and you're basically -blam!-ed, as the only counter to that appears to be Nova Bomb.
Two changes that need to be made:
1) That Ability recharge rate buff that's given to players when near their partner? That needs to go. Replace it with buffs to mobility, resilience, and recovery.
2) Heavy Ammo should be removed.
Or they could not bother with this failed event. It was the least favored event they ever came up with in D1. Not sure who thought trying to revive it for D2 would be a great idea.