I think we should be able to bind a weapon set to a specific attunement. Only changeable outside of combat.
It would help us be more adaptable to the changing nature of combat. Would help especially with D/D being pigeon-holed into melee combat when situations often demand ranged and vise-versa.
Some examples would be fire/staff for long range and AoE, air/S/D for fights requiring mobility, water/staff for healing, and earth/D/F for melee/defense.
I can foresee a few balancing issues like having access to multiple auras and weapon swapping sigils. But I think shared ICDs (I believe sigils already have it) would solve that problem.
And face it this change would actually give us a reason to use the focus. We all know that thing is for the most part useless.