BtA items is not a problem, you can buy shared bank + additional character slots (as many as you want).
But BtC items is a problem.
Actually I have more BtC items than BtA items (raid loot, epic items, other stuff, etc.).
So why Turbine doesn't want to sell more bank upgrades?
Not sure about other players, but I'd like to buy like 10 additional bank upgrades (yes, +200 slots).
I want to have all important items in the game (on the same character). Why not?
I have ingredients for many epic items and I'd like to test them and keep them (even useless ones). Also I would like to farm more, but it's pointless at this moment, because I'm stuck with a small bank space.
Please consider that.