Now that would be interesting, to drag Arthas back from hell just to have him sit in lordship iver the people he damned in the first place.
I mean there are some ifs and buts, but frankly even treating him like Kil'jaeden did Ner'zhul would not make the forsaken trust him.
But admittedly the idea of fishing up Arthas from the dump and dumping him in Lordaeron on a dumpster throne seems mildly entertaining.