I'd love to hear your complaints about Halo 4. Take this opportunity to elucidate on them.
Very well good sir. Long post here, sorry. This is just off the top of my head.
Deadly Cyclone's Exceptional List of Things Wrong with Halo 4
(Read in Morgan Freeman's voice)
Campaign
* Story issues - Within the story 343 missed a huge opportunity to explain the Didact at all, and hid a lot of useful information in terminals. People that aren't huge Halo lore fans have no idea who him or other big characters are in this game, and will be very confused at the difference between Prometheans and Forerunners, and how humans were around when the Forerunners existed at all. Not to mention the whole "humans were space-faring but got knocked back into the stone age after the Human-Forerunner war" thing or the "humans beat the flood once a long time ago" thing.
* Gameplay issues - While I like the concept of the Prometheans, and how they look, they just aren't that fun to fight (with the exception of the crawlers. The watchers do the exact same thing every time you shoot them (start flying in one random direction) and the Knights basically just hop back and forth until you headshot them for the 30th time. Overall (as Dax had mentioned) the encounters just weren't quite as good as say, Halo 3. By the end I had each enemy down to a science. Headshot Grunt and Crawler. Shoot Watcher first. Headshot Knight until shield pop, then finish off. PP or Needler on the Elites. etc. I'd go deeper in depth here but it would include spoilers, so I'll hold off. Let's just say I wanted a few more huge set pieces ala boarding the Scarab in Halo 3.
*Oddities - Where do drop pods come from? Where do these "outlier" Covenant ships keep coming from en mass? What do the other Covenant think, and how have they not found Requiem? We should see Covenant fighting Covenant fighting Prometheans fighting Humans.
Multiplayer
* Guns - The DMR is overpowered. I want to use the Light Rifle, or Carbine, or the BR, but can't because I generally get donged on by a DMR across the map. Hell, the BR was my favorite weapon in Halo 3, and I almost never pick it up in Halo 4 because I'll die on any larger map. Make the DMR more shots to kill, or decrease its range.
Secondly, the Promethean weapons are too close to the human ones. I love the way they look, and am fine with having a base set of similar weapons to balance off of, but with the Covenant Bungie was able to give us a few similar weapons, and then some crazy stuff we'd never seen before (Needler, etc.) In Halo 5 I hope to see a full Forerunner slate of weapons, with some highly original offerings. Also nerf the Promethean Pistol.
Finally,
WHERE IS THE AMMO ON THE MAP. I HATE running out of ammo on Ragnarock. An ammo box here and there won't change the gameplay that much.
*Unlock System - I am for an unlock system, but the more I play the less I want guns or perks to be part of it. Keep the unlock system for aesthetic purposes only. Add more armor, more gun skins, etc. but keep gameplay affecting items out of unlocks.
Secondly, make more levels and bring back the fun Halo-themed levels. I like the idea behind Specializations, but I loved the Bungie levels with special symbols, and overall how long it took to get there.
*Maps - I love BTB, let's just get that out there, but we need more small maps. The other day I was playing and realized that Halo 4 feels like Halo 4: BTB edition. Haven is one of my favorite maps, and that's because I think it feels closest to that Lockout or Ivory Tower feel of close chaos. We can keep sprinting in, just make some smaller maps. All of the maps 343 made feel great (except Complex, fuck that map) but they all feel like I'm playing BTB despite the mode I'm in.
*Visual Rank - Bring it back. 1-50. On the screen. Enough said.
*Drops - I like the idea of ordinance drops in Infinity gametypes. I no longer like the global ordinance. Bring back static on-map weapons with timed spawns. I want to know the sniper will be in this specific place on Exile, etc.
*Join in Progress - It's fine for the most part, but there needs to be an option to get a brand new game and not get put into in progress games. If a game is more than 3/4 over it just shouldn't put you in it.
*AAs/Perks - Get rid of Jetpack and Promethean Vision completely. Invis is fine with me still. As for perks, they don't rub me wrong yet because they don't seem to do much. I would say if flinch bothers people that much just get rid of it, don't lock it behind a perk. I tend to feel better with perks like "more grenades" or "more ammo" and less ok with perks like "fast reload" and "bigger explosions" though.
*UI - Get rid of it all. The only UI I like is the start menu box that you can get to everything from (spartan, challenges, game settings, etc.). The lobbies look bad and I hate that once I vote it pops up all the player cards. You should be able to see the map/gametype and votes all the time. The UI needs revamped for Halo 5 outside of the start menu thing.
*Lag - What the hell? Why does it lag so much?
*Vehicles - Why so few? Where are the Forerunner vehicles? Promethean warriors can teleport, can all Forerunners? If not, where's the Forerunner tank, or chopper?
*Bring back FFA and add objectives to BTB.
Random
* Theater - Really needs to be taken to the next level. Needs campaign theater back, and add features like output to Youtube. Montage maker. Save screenshot to dashboard for personal themes. Ability to watch live matches (watch an MLG tourney on Halo 4 live, etc). There is SO MUCH you can do with theater that did not get done.
*Spartan Ops - Went over this already. I like it, but I don't love it. I want it to be the means by which 343 can let us experience things we'd never get full games on. ODST missions. Spartan 2 training missions. John's first insurrectionist mission. Onyx missions. Etc, etc. Also for the love of Jesus figure out how to make Spartan Ops without input lag. It's better than Reach, but I still get it.
*Firefight - Bring it back. Limit it to Spartan Ops maps if you have to.
*Forge - Needs the same "next level" as Theater. It won't ever be a map editor like some games have, but we should be able to have more colors, more control, and more land formations. I'm not a huge forger so I'll miss a lot here.
So, this is all I have right now. I have more, but I can't think of it off the top of my head.