What apparently inactive researcher would you most like to see return?

[ReneZ]

And there was this guy that would always post (back on the mailing list days) crazy stuff, always in MiXeD CaSe LeTTeRs, about how things came to him in dreams, and that he could never really explain what he meant when he posted. No content of any use, but he was always really good natured...

That would be Steve Ekwall.
I don't think he has ever posted here.
He gets some attention in Nick's book.