In less of a ranty way, i agree with Mayvind, i would say another Nerf is not nessecarily the way.
As we have seen, many nerfs have taken place across the server with nothing to fill their void, Higher Levels are strapped for choice.
I'd say, up their CR to meet their change and current challenge, lower the amount of Dispells they spam are both great options, their other stats are meant to be high, they are not impossible, but they are -very- challenging, wich should befit a Devil Legionaire, why remove when you can improve..