Locking out matchmaking for Easy is ridiculous; a completely baffling move.
Normal is unbelievably difficult with rando's -- the only full Normal match I completed with rando's, I had to do wave 10 by myself as the other two would get downed too fast and/or wouldn't go after the warlord (purple pirate guy).
Last night, me, somnium and bamf completed about 5 matches on Normal and we were having a blast. The crazy round modifiers can be hilarious and very punishing, the stand-outs we played were:
Glass Hunters
Dozens of Hunters bum-rushing while you're in a siege zone, only the hunters are very weak and die in 1-2 shots. Just a never-ending stream of *heavy breathing*
Charge Melee
Charge melees are 1HKO's and hit with an explosion of confetti and smoke.
Hydra Enemies
You kill and enemy and more of their type will spawn. We had about 7-8 chaingun guys at the end of the round.
Mirror world
Flips the world around. We had it coupled with Treasure Hunter + No radar, on an unfamiliar map, as well.
They do need to tone down the armor guys in the later waves though, or at least bring back 1HKO headshots across the board, so you just have to fire twice, at minimum.