I'm unsure if you meant character level or attribute level, but the latter could work as a very simple way of including attributes as minor factors.
The idea you gave me would be that the DC to resist is 10 + the attribute score used to invoke the bane - the attribute used to defend against it (not used to defend in dice, just in fluff), though it can't go below 10.
So if an elementalist with energy 6 would fight a hero with might 5 and movement 3, and the elementalist would freeze the hero's legs (immobile) and set his upper body aflame (persistent damage), both using his energy score of 6, the hero would attempt to resist both:
This hero obviously tries to use his greatest strength, his physical might, to his advantage. He immediately decides to simply smash the ice to break his legs free, so the DM allows him to substract his might score from the DC, but he can't think of a way to use his might to extinguish the flame, so he chooses to use a brief vacuum with his control over air instead, so the DM allows him to substract his movement score from the DC.
He simply rolls a d20 for each bane he attempts to resist, but his DC for Immobile would be 11 (10 base +6 energy -5 might) while the DC for Persistent Damage would be 13 (10 base +6 energy -3 movement).
I think this would keep it simple enough, and it would generally make banes slightly harder to resist, while rewarding players who describe how their characters attempt to fight off these debilitations, likely resulting in a more descriptive combat and more satisfaction when players play the scene of their (hopefully) success in their minds.
P.S. Why do I always feel the need to write such long-winded comments even if the idea is so simple (at least in my mind)?