You hated Armor Lock because it's fucking bullshit.
That's what you were screaming, admit it. You'd have meticulously dropped someone's shields, or waltzed around a corner with the rocket (read: portable nuke) launcher, and just as you let that killing round fly... bzzzap. Nope. And what flew from your mouth?
"Fucking bullshit."
The problem with Armor Lock was complicated; a lot of factors were at play. People labelled it a "pause button" for combat, a get out of jail card for bad play, and so on and so forth, and I don't really want to get into all the reasons it sucked. But an important part of the frustration it induced was that the pause button it hammered down was suddenly and disturbingly unexpected.
There is a narrative in your head in the kinds of situations described above, drilled into you by hundreds if not thousands of hours of play (hint: it's "I'm winning this fight"), and Armor Lock just rips up the script. You knew what should have happened, and yet something outside of your control, something barely inside the other player's control ("press button to not die"), cancelled it in an instant. No fair. Bullshit.
Sure, we want games to be unpredictable to a certain extent. But we want that unpredictability to be introduced by human action. We want someone to strafe a way we didn't expect, and then pull out a perfect four-shot with their shield already down while we fumbled for the headshot. We want them to skip a grenade so sweetly into our teeth that we shake our head in admiration, not rage. We want them to take off our head with a no-scope when we so nearly had them, damn it ... so why are we smiling? Because those deaths were our fault, and theirs. That's what we tell ourselves -- that if we could do it again we could do something better, crouch that little bit sooner, pull up our reticle that little bit faster... next time, next time. Respawn, fail again, fail better.
Armor Lock is from that dark hell of gameplay where it seems like there wasn't anything to be done. Sure, we could have found out from our teammates that our enemy had Armor Lock at the press of his thumb, but we still have to play along, still have to shoot him knowing that... bzzzap. Nope. We did everything right, and we still didn't get the appropriate result, because there was a joker in the pack, and we got trumped.
Now I want to paint a nightmare scenario. This is scaremongering, of course, but... Halo 4 potentially has one hundred jokers in its pack. One hundred little Armor Locks hidden away in some frightful combination of weapon and armor and loadout and circumstances and whatever else. One hundred little moments of unconquerable frustration -- none of them nearly as extreme or blatantly 'bullshit' as Armor Lock, obviously, but still irritating in aggregate -- when someone does something you couldn't predict unless you treat every encounter as open and unknowable. Unless you go into every fight with your shoulders shrugged, expecting anything. Meanwhile, you don't know how many rounds are in his gun, how many grenades he can throw, how long it takes his shields to recharge, how he's even going to move. Often you won't know what rabbit he can pull out of the hat next, because it didn't come from the field of play; it came from the start menu. You'll do your best, but quite often you will lose your life, your streak, your game when the die your opponent rolls comes up with seven pips.
Unpredictable opponents are fun; unpredictable systems are not. There's a reason chess is regarded as the purest game of skill: all the pieces are showing. In Halo, you should be able, ideally, to approach a situation with your eyes open and your wits about you and your thumbs twitching, and be confident you'll be beaten only by a better player, and not trumped by some shark repellent spray from their unknowable utility belt. Figuratively speaking.
I want so desperately to be wrong.
