AR and SMG need nerfing,
Sniper scope needs to be changed, the blue tint when scoped makes thing hard to see.
Clamber is annoying because you cant shoot while doing it, thus if you clamber and you enter someones line of sight, you're pretty much dead.
But I like the lower jump height, makes bunny hopping better, and gameplay doesn't feel as 'floaty' as it does in other games.
Sprint should be removed, but before you guys flame me, here's why: I rarely ever use it. It stops you're shields from recharging and there's a delay before you can shoot when you finish sprinting, thus sprinting around a corner into enemy line of sight = disadvantage for you. It has no benefit being in the game other than to travel distances quicker, it also doesn't make you run that much faster. It should be removed, and spartan base running speed should permanently increase. Let's say for EXAMPLE default speed is 100%. Sprint makes you go 150%. Sprint gets removed and running speed is bumped a bit more than halfway to 130%.
Now before you people say "mah supersoldiers they should be able to sprint" think about this. NO ONE complains and says that Counter Strike needs to evolve because there is NO aim down sight or sprint. So why does Halo, a game set 500 years into the future, need to be realistic? CSGO is set in our time, yet the soldiers don't ADS or even sprint. CSGO has been around for not much longer than Halo, and it has still survived and is currently the most popular FPS on PC. This is just solid proof that 343i want Halo to be mediocre, and not different.
Spartans are actually more advanced than you think. I believe they should be able to run as fast as sprinting speed and still aim from the hip. The weapons are linked to the Spartans HUD so they don't even need a red dot sight to look through. IMO the way that the Assualt Rifle scopes in, is really cool and that should be what it looks like on all guns.
If sprint is removed, they can still keep slide and shoulder bash, the controls scheme would work like this: Holding down melee button while moving will charge up a bar for half a second, then releases shoulder bash, quickly pressing melee button results in a normal melee. Same deal with slide, hold down the couch button for half a second and you slide. Easy.
For the people complaining about ranking system, it's actually pretty good in my opinion. Halo is a team game, there is no 'i' in team. The skill rank for team playlists should indicate how well you work with a team and your skill within a team environment, not individual. FFA is the only playlist that can really determine individual skill.
I think you should only be matched with players in your own division. Gold plays with Gold, Onyx with Onyx, ect. But semi-pro and pro should be able to play with/against each other.
I also like the idea of how the Prophets Bane increases your movement speed. Would be cool to make certain weapons change your speed, such as any pistol weapons make you run faster when holding them out, and heavy ordnance weapons like Rockets, make you slower. Sniper, DMR, Carb BR ect should keep you at default speed.
Oh almost forgot, bring back items from Halo3 like bubble shield and power drain.
If 343i implements the changed I said, I think it could possibly be the best Halo game to date. Now, these are just my thoughts so far after playing the game for 3 hours. If anyone can give me reasons as to why my ideas wouldn't work, then please do.