I'd like to see him make an appearance at least, although being a squad member wouldn't hurt either. He was a rather likeable character, certainly not as exotic and interesting as the aliens but he was an honest, no-bullshit soldier, who would give his opinion every now and then without sounding cocky. Of all the squad's human characters in ME2 I propably liked him the most. Zaeed was a rather selfish mercenary with some funny one-liners, Jack despite her good "excuse" to act like a ***** was exactly that, a *****. Miranda seemed like a diva ice queen, and out of the airlock she goes. Kasumi was alright too.
Also, I found his loyalty mission to be one of the more interesting ones. Can't wait to see on which side he ends up in ME3.