Like what? Load outs? AAs? Thats a matter of people not being able to adapt (or change) and to a certain degree, evolve to new gameplay features more than it is a "game" problem.
If you ask me, its old Halo fans stuck in their old ways. Unable to accept any type of major change.
I think we're open to change. It's just some people hold on to more things that make Halo, Halo.
For some, Halo is only shields, sci fi, reticle aiming.
For some, Halo is all of that plys the idea of equality among players, of fairness, of little randomness.
For some Halo 5 could implement Aim Down Sights and as long as it has shields and is in the halo universe its still Halo.
As for what we saw, yeah some people including me wish loadouts were never a thing. AR vs BR was a huge community war in the other Halos, and being able to choose your starting weapon is a change I welcome. But being able to choose game altering abilities and now entire perks... some of which are only available to those who bought the LE/got the spec code/most of all, played a SHIT ton.
But as for what we saw coming, at the top of my head, camo being back (despite perfect opportunity to make it a ordnance power up) DMR being too powerful, instant respawns, random ordnance bullshit, flag auto pick up (the actual changes to CTF can be debated, but flag auto pick up SUUUUCKS). We didn't find out what the boltshot did until late, but people were calling them out on a insta kill loadout weapon. I know I was a big hater of plasma pistols/nades in BTB from way early on.