Here is a recent scenario i encountered playing halo reach:
i was playing team slayer on sword base, and i was in a 1 on 1 DMR dual with some scrub......their team was 3 dead at the time and i managed to get him one shot: requiring one more shot to the head for the kill. Then what do you know, he goes into armor lock for 10 seconds or however long it lasts, which allowed enough time for his newly respawning teammates to come up the stairs behind me and triple team me. I was way better than all four players on the enemy team...they weren't even close to being on my level. Armor abilities like this take away the competitiveness, and also decrease the skill gap in almost every playlist. WHY DO THEY HAVE ARMOR LOCK!? IT RUINS THE GAME FOR GOOD PLAYERS!