This is just a taste. A lot of things the vast majority of players won't notice, but here's one or two of the more visible and necessary changes. Note that NONE of these has been done casually. All of this has undergone testing and tweaking. Thanks to Jeremiah and Sketch for the new info.

Sudden Death has been removed from all Assault variants to prevent griefing. If you think that griefing was a legitimate tactic, you are simply going to have to learn other basic skills. You all knew that doing it was bogus, aggravated the other teams and was fundamentally imbalanced. Did we have any responsibility there? Sure. And we've fixed it. Thing is, we accept all our responsibilities, while griefers continue to defer theirs. Stop cheating, stop griefing, and don't cry about how it's our fault for making it possible. We had issues with our designs that did make it possible, but nobody forced you to exploit them. Especially when other teams DON'T do it. Griefers who complain about OUR responsibility to stop them from cheating should dial 911 and ask for a Waaahmbulance.

Round time for Assault variants has been increased globally to give teams a better chance to score since sudden death is gone. That should mean more epic struggles, and some maps, like Headlong, will become very, very interesting…
 
…especially since we've removed Banshee from CTF and Assault games on Ascension and Headlong. Why? Because griefers will surf the bomb to unreachable places anyway, just to be jackasses.
 
No more Plasma Pistol / Battle Rifle ownage in Slayer games on Beaver Creek or Colossus - we now use Human weapon sets for Slayer variants on those two maps. This will be controversial and we understand there is some small skill required to use the combo, but frankly it has become tiresome on those maps. It takes far more skill to win without that combo. More skill = more fun, right?
 
Motion Detector (radar) has been removed in all head to head playlist variants. This one I'm personally ambivalent about. Partly because of my inability to look at radar while fighting/getting owned. Partly because it sometimes adds a layer of strategy (creeping on objective based games, being a good example) but we hear the thronging masses. Loads of noise demanding its removal and almost total silence on the opposite opinion.
 
The majority of game variants on Coagulation and Burial mounds will now start players with Battle Rifle and an SMG - exceptions include games such as Team Snipers, Team Rifles or other variants which feature specific weapon sets. THIS one we expect universal approval on. Now that I can actually shoot the Battle Rifle with some modicum of skill, I will be putting it to good use. We've done more palatable Battle Rifle starts on the newer maps too, but since they're not in matchmaking yet, you'll have to take our word for it.
 
We've added King and Oddball variants to Head to Head to encourage more conflict, less hiding and more variety.
 
No more Phantoms. You'll have to custom game that one. Phantoms was a rarity anyway. Now it's just super-ultimate-rare. That is to say., gone.
 
We've added new CTF and Assault variants which feature Covenant vehicles just for variety. The Spectre is making an appearance and should make for some interesting encounters. Shouldn't really change balance too much though.