Since you said its the only FF game then you wouldn't realize it's not as bad as you're thinking and quite staple in the series lol. I agree, you can have an engaging MMO without cumbersome mechanics...sadly we've yet to have one.

Basically you wouldn't be "locked" out, you'd get a potency hit (which means no facerolling, everyone wins). The armor thing in single player games wouldn't let you progress until you equipped a certain other types of armor (no iron/mythril etc) or the 'reverse' effect where weakest = strongest and strongest = weakest.

It's really not a restriction, it keeps a game from being shallow and lifeless, FF games have so many interesting mechanics people are afraid of.