Massive storage space issues though. Also not a fan of this at all. If I have something then I should be able to use it.
I hear what you are saying, and though my wait (for decent gear) wasn't as long as some of the RNG horror stories I've read about, I still feel like I "earned" my PBM (and other shinies) with how long I had to grind for it. However, if the cost of being overpowered in routine (and perhaps threatening) is eventually burning out from disinterest/lack of challenge, then I might consider some level restrictions on the gear to delay that process.
Nobody can force me to promote, so if I felt that strongly that I had to use my PBM or else nothing, then I could just remain at 20. I'd eventually lag behind those players who regularly promote, but the choice would be mine to make. It isn't like it wouldn't be in my inventory; I'd just have to use other weapons temporarily while leveling to 20 again. Maybe it would be nice to get a chance to use all those different lowbie unique weapons (that I never had until it was "too late"), to really get the most out of them and appreciate them without feeling like I was deliberately gimping myself by not using the absolute BiS. Even the levels up to 20 would have meaning again, knowing that as soon as I hit xx I could use yy again. I dunno man, I'm not married to the idea, just something that I had thought about.
As far as the storage issue is concerned, what can I say? Yes, we need more storage (and less mandatory crap taking up inventory slots [I'm looking at you, Alchemist armors... ]), but if they refuse to give it to use or it is somehow technically not feasible then that would just add another level of difficulty to the game. At the risk of sounding like a freshman econ textbook, scarcity and choice would just be something else we had to deal with. Maybe I don't actually need to have that Gift the of Mountain Father taking up an inventory slot if it is going to cost me not having something else I valued even more.
Anyway, /end blah blah blah.
Gonna go kill some ****.