Halo.
CE, 2, and 3 featured multiplayer where two teams started off on even footing, the difference to be made by skill level and map control. Power weapons and pick-ups spawned on the map and it was up to a team to control those in order to accomplish their objective.
Then Reach came along with Armour Abilities and Loadouts, among other things, which fucked it all up. Armour Lock negated everything: Vehicles, grenades, rockets, etc. You could shed plasma grenades with the fucking thing, which means that a successful stick, which was once a point of skill, could be negated with the touch of a button. Jetpack threw a wrench in map movement, Active Camo gave campers newfound invisibility and even radar jamming (don't say it wasn't for camping, the camo didn't even work if you were moving). They removed melee bleedthrough on shields so it became more effective in CQC to just double-melee (what was considered a noob tactic in previous titles) than it was to attempt to outmaneuver your opponent. Bloom added unnecessary randomness to the mid-range combat that dominates Halo's gameplay (Pistol->BR->DMR). Sprint being added as an ability, meaning that A: The gameplay was slowed down in order to make sprinting a commodity, and B: One had to sacrifice their advantageous AAs in order to have any semblance of speed. Sniping became almost too easy, for Halo veterans, as the slower run speeds and lower jump heights made it seem like playing a Custom Game where everyone had to walk.
Halo 4 has most of the same flaws, only now Sprint is a function independent of AAs: Better, because you no longer have to sacrifice an ability in order to actually move, right? Actually no, because the fact remains that everything is slower when not sprinting and you can't fire your gun while doing so, meaning that by default the combat is slower that it should be.