I as well feel Imperius is a misunderstood character.
Although I do fear a situation where the Nephalem in the next expansion (if there is one) will hold the fate of the angels in their hands and the Nephalem's possible choice to phase out their kind.
It's weird but I forsee some kind of repeat of the Sin War going on here, except now it won't be the humans/neph that are being voted on. Ithereal alludes to this exact same case in Act IV.
I could def see a scenario where perhaps the Neph choose to end the eternal conflict by making all angels and demons human in some form like Tyrael. Imperius would undoubted hate this and that may bring about a conflict with him and the Nephalem, as he is certainly too proud of his angelic heritage to ever accept becoming something similar to what Tyrael is now.