Silly idea and goes against everything they have established in this game so far.
Let's just focus on your concept of "locking armors" to each knight. This would prevent those armors from being fused into something else. Since they went to all that trouble when this happened with the summoning stone, why undo all that effort.
When you have basically every armor in the game maxed, how frustrating must it be that just about anyone can still beat you in any given battle because they picked the correct armors? If you don't want the chess match of armor selection, then maybe this isn't the right game for you any longer.
At least here the "randomness" of misses and extra crits, are nowhere near as frustrating as the buffer zone in KA (where being 40% stronger than your opponent is no guarantee of success despite it being purely att vs def numbers based). It is still frustrating, but somehow it seems more tolerable - maybe because you can see it, and this make me feel like I'm not going to find the wizard hiding behind the curtain.

Someone mentioned making names unique only - not only is this tough to do (apparently) for GREE at this point, but they never bothered to incorporate this in any of their other games, so it seems unlikely they will ever add it here.