What I would like to see in the armory system is something like this.

Let me take abilities from all classes that I have leveled, with the catch being that the 5 slots I can use are gated by a level restriction.

Slot #1 can be any skill lvl 45 and below

Slot #2 lvl 35 and below

Slot #3 lvl 25 and below

Slot #4 15 and below

Slot #5 10 and below.

Also, If I can cross class skull sunder, for the love of god let me use the whole combo.