All of the abilities, especially the roll/dash/fly are what really annoy me. I also do not like the starting loadouts. Everyone spawns with the same simple guns and if you want better, you fight for it. Depending the game type the starting guns can change.
You can argue with me all day that that is not how people want it, but lets face it Halo multiplayer isn't the big name in the business anymore, and people wonder why it isn't as popular as it used to be with Halo 2 and the beginning of Halo 3. I think these loadouts and abilities are part of the problem. Seems like all the games are trying to mimic Call of Duty. I will admit, after Reach I thought Halo Multiplayer was a lost cause, but Halo 4 was refreshing, but still not Halo 2.
This article touches on the issues the newer Halo's have had with multiplayer...
http://www.ign.com/articles/2014/06/09/the-real-reason-halo-the-master-chief-collection-exists