@Razvan said in Suggestion: Different spells have different armor requirements:
This would make tanking quite awkward both in pve, because they have to carry a bunch of sets and change whenever they reach the next group of mobs
But it's like that for everyone. 
That's the point of this game, to have multiple sets of armor, and then prepare for expedition, gear for what you aim, and embark on a journey. Do what you wanted then go home, rest, recover, unload booty, prepare new gear for what you want to do.
This MMO is not supposed to be, go around, kill anything in same gear, roam how long you like not carrying about bag space, do what you like without ever returning home to re-prepare. 
By having an ability to mix and match, you can make yourself geared towards situation you want to do. If task is too hard for one person (lack of gear maybe, or simply too hard in any other way), then find a party, gear up for your role in party, AND situation at hand and go. After the task is completed go home and gear up for next task.