This is a very good idea.
I'd like to see like spells like in PvP, let me explain :

We have differrent level of relic from Relic ilvl80 to zeta ilvl 135. Adding new spells or buff why not, but I thought it would be better to add some additionnal traits to the skills we are using just like the level of a skill in PvP. That way, I am main bard so i take example with Bard :
Blood letter critical : would have increased damage, potency of Dots increased.

An other idea would be to add a CD on the weapon so the user gets a special buff/attack.