I don't like mayhem because of one thing: Defenders. Especially teams filled with them.
I'm calling it right now, 6 man fireteams dropping into IB and camping in multiple bubbles for the entire game.
If you can get at least 3 defenders in mayhem, you can just sit in one corner for the entirety of a match and generate infinite orbs for your allies. I have seen opposing fireteams, including my own, do this in mayhem matches. These matches are generally one sided with the bubble camping team winning flawlessly.
Then those teams you went up against have no coordination. Teamwork is required in IB, and if people complain about the only class that has the least usage in PvP, they are just bad.
Did you just read what I said, or no? A Striker or a Voidwalker with a well placed super is what a good team will work with. Defender is just doing as the name implies.