Halo 4 was/could be a brilliant game but the multiplayer, customs and forge are completely ruined by a plague of bad design decisions.
I genuinely despise the game despite being a long standing Halo veteran and fan. Campaign was best one yet, but the multiplayer... it's simply not competitive in any way any more, and while the learning curve for previous Halo games' multiplayer had a exponential gradient, Halo 4's has been stomped completely flat - it's been so damn noobified there is no more room for improvement beyond sitting in scope, vaguely aiming in an enemy's general direction and rapidly pulling the trigger.
Here's just a few of 343i's poor design decisions and shortcomings:
On my X (red dead-X and shooting/shot-at indicators above friendly players) removed;
You don't get shot out of scope any more - this heavily encourages camping cross-map;
Can't drop flags;
Ordinance ruins map flow, skews game outcomes and murders competitive play in its sleep by adding a top-heavy truckload of luck to the game;
Maps overflowing with vehicles - Big team was always about more player numbers with vehicles to support.;
Stopping power (movement crippled when shot) is overwhelming and never used to exist in Halo;
Bullet magnetism (aim reticule turns red, your bullet will hit your target} overcompensates so much, it's near-impossible to miss a shot;
One flag/bomb objective games & infection removed (limited custom game options hamper workarounds);
Far fewer custom games options than Reach OR Halo 3;
Forge objects don't spawn in simultaneously when object timers applied, or at all if a player is nearby (they did in Halo 3 & Reach);
Join in Progress and matches beginning with unbalanced teams is a flawed practice, good in concept, doesn't work with Halo;
Betrayal system is crap - it hardly works at all; and
The UI (menus) are uninformative, basic, a navigational nightmare and simply unintuitive. Reach had an absolutely flawless UI.
There are many, many more design flaws and shortcomings I could rag on about that need rectifying, but these are the most notably ill-conceived. It absolutely infuriates me. I haven't gone into detail on most of those points but if anyone doubts me, in a PM, I could easily justify how they can be fixed, altered, or in a few cases, removed from some playlists to shape the game into a better competitive Halo multiplayer. I do welcome a lot of their additions (forge Magnets, JiP, Loadouts, Spartan Ops, perks, specialisations, etc.) but they have fundamentally broken what makes game Halo by changing and removing features that worked perfectly fine before and it is not fun for me or any of my friends to play any more, because of these poor design choices.
Now, no game is perfect upon release but Halo 4 is flawed to the core... a core which still contains the essence of Halo, but it's covered in a tonne of total shit. The few people defending the game clearly haven't played much Halo before, or are being naive (I hate to say it, but you are - this game is not Halo), because there are some really tragic, almost-rookie mistakes made on the part of 343i; which is surprising considering they're made up of industry vets and former Bungie employees - but that's what happens when you don't do an external beta-test on an enormousness project that requires fan-based feedback.