Right now this is probably the only MMO that comes to mind that only allows you to gear up one class at a time. The armory system really needs updating, it's fine to use modern MMO systems with lock outs and point caps but the armory system very much conflicts with that as is.
I'd really like to be able to earn loot and points by the class. You'd have to take a couple of steps to make sure it isn't abused, like restricting purchases and off-rolls to an extent in gated content but in the end it'd be a huge net gain for those of us who like alts and have little to do.
There's almost no middle ground content as is, things tend to be extremely easy or extremely hard and that's frustrating but at least allow us to spend some time gearing up alt classes until maybe something can change in that area.
I just want to say I took a break from halfway through 2.3 all the way until 3.0 that I likely wouldn't have if I had more alt support and middle-ground battle content.