I think one thing worth considering when calling for increasing this or removing that limitation or so on, is what is the worst case strain/stress/load on the system? In that light, I think some of the restrictions, on both plates and where you can apply them, may be due to the worst case scenario, of someone swapping glamour plates in rapid succession. Normal glamouring is slow, one at a time, not exactly a heavy load to process. But with plates effectively applying, what, 10+ glamours at a time, quickly enough that you could switch and apply plates faster than you could even switch a single glamour manually? And compound that with the scenario of every character in the zone doing that all at the same time.
Sure, it's unlikely that 100+ players in an area will all get together to rapidly change their plates all at once. But if a situation like that could potentially crash the servers, they're naturally going to impose restrictions to keep that from happening.
At least, that's one theory I can come up with for why they can't give a little more freedom with the system.
