I'm questioning Halo 4 in particular, though.
Much of this is removed with the "Random" ordinance system.
Instances of game breaking, time ruining ordinances;
1. Having Rockets spawn Twice infront of my own base, along with sniper, during a single game of CTF
2. Enemy Teams being rewarded heavily with Power Weapons in Infinity Slayer
3. Enemy Teams being rewarded heavily with Snipers, in particular, during games of Infinity Slayer
While Team Regicide fixes issues like this with smaller maps and the removal of personal ordinance, 343 has limited the amount of hoppers that give us this flavor of 'classic halo'. This flavor, though, still has the potential to be ruined by Custom Classes. The Bolt Shot in particular is what I'm talking about, as players are now spawning with Mini Shotguns.
As for gameplay variety, I feel 343 went about the Custom Class system in a bad way too. I recall an interview with a Multiplayer Designer talking about how each team should have at least one person spawning with Stickies and Plasmas. The issue is that EVERYONE can do this now. Tanks are rendered near useless, Default Warthogs are rendered completely useless, and don't forget the fact that Banshees can still be taken down with Snipers and DMRs. The variety of infantry to vehicle combat has been completely destroyed. In all honesty, the only vehicle that you can have constant success with is the Gauss Hog, and that's only if you play Extraordinarily cautiously, staying to one side of the map and having your gunner snipe enemies from afar.
I feel Blops2 has worked out many of the kinks present in past COD iterations in terms of Weapon balance, especially with the change of Weapon Altering "perks" now being attachments and player base traits being confined to perks and broken up into multiple color categories. While more attention has been given to personal customization, this game is dominated by Teamwork and cohesive map control.
While there are still some issues (The new MultiTeam mode needs work, for sure), There are just many areas of the game that completely blow 343 out of the water.
Last I would like to point out- I was able to put the disk in, join a party, and find a game in under 3 minutes last night. This is not only the fastest I've been connected to a multiplayer game (ever), but It's the best COD has ever performed within two weeks of launch!
Don't mistake my analysis for complaining. I'm just pointing out flaws that have dampened the Halo experience and changes that are giving COD even more dominance in the FPS arena.