I really liked it initially, but it's become very clear now that there's a lot of issues and Halo 4's multiplayer is essentially a cut down Halo: Reach with some bizarre fusion of CoD and Battlefield elements inferior to every game in the series.
Stuff like all the little things that worked great in the other games that have been removed or 'fixed'. Stuff like teammate damage/death markers, getting knocked out of scope view when hit, droppable flags and bloom getting taken out. Now you can't tell what the hell is happening to your team, can nail a guy with ease even while getting shot up, basically get punished for trying to play CTF properly and can snipe guys with anything that has a scope without even trying ('cept the pistol, which has some degree of accuracy loss.) And what happened to races and headhunter?
Then there's the stuff they've added.
While I'm not adverse to the idea of a loadout system in a Halo game, I am adverse to the idea of perks in one. Changing a players capabilities like that really doesn't feel right. Automatic loadout guns aren't worth using and grenades have been really messed up.
Regicide is interesting in theory but doesn't work very well. If you do well then you essentially get marked for death. Do really well and after you die, you'll be marked for death again just after being killed. If someone just so happens to feel like getting a ton of regicide medals and has a DMR, you get to get spawnkilled repeatedly for doing good. You get some bonuses for being king, sure, but they don't come into effect until sometime after you get crowned, and if I remember correctly they're time based rather than kills based. If a guy becomes king, hides somewhere and is lucky enough that the other guys are busy wasting each other rather than finding him, he gets buffed after a short while. It'd be a hell of a lot better if the king got buffs for contining to fight and kill guys. Say 1 kill as king gets you a speed boost, 3 an overshield, 5 a damage boost. The worst part is its the replacement to good old Free-for-All.
Power weapons have gone completely crazy. In the earlier Halo games they'd kick ass but still had distinguishable roles. The sniper rifle was the sniper rifle, the rocket launcher was the rocket launcher. It got bended a bit with weapons like the Fuel Rod Gun and Spartan Laser, but these guns too had different roles and strengths and didn't infringe on the other weapons too much. Now we've got stuff like the SAW, Incinerator, Binary Rifle and Scattershot, which are essentially assault rifles, rocket launchers, sniper rifles and shotguns respectively, except better in every way that matters. Then there's the crappy power weapons. The railgun comes with little ammo, is a ***** to use thanks to its charge time, epic glow and lack of a scope, and its only advantage over anything else that does what it does is its blast effect, which is pitiful. The concussion rifle's rounds are very easy to avoid and its simply weak and a pain to use overall. The Needler has gotten a decent boost but still isn't good enough to be effective at much beyond surprise attacks at a very particular range just beyond that of shotguns and too close for scoped weapons. This blatant imbalance just feels...dumb.
Then there's some more big playlist, matchmaking and game mode issues. There is only one mode to each playlist, Free-for-All has been replaced by a dopey mode, Flood can longer be tweaked to allow the zombies to have particular weapons, match searches take too long considering they don't even work well, you can routinely get put in a match with players on the other side of the world despite there being tens of thousands of players in the playlist you just joined, when searching for a match you can't check an option to ensure you don't get put in a match in progress, and perhaps worst of all, 343 didn't even add some type of old school playlist that retained the old Halo goodness free of all this crap.
Actually, there is one improvement.
Throwable Oddball.