It's funny I just watched Encino Man on tv the other night, and I saw a guy that I thought looked a lot like Ke Huy Quan. When I checked the credits, he was listed as Johnathan Quan, which when I looked up on IMDB, turned out to be Short Round himself!
I think it could be cool to see him make a guest appearance, just for a bit of closure. I've always wondered what happened to him, because I couldn't see Indy just ditching him. I know not everybody wants all the characters to reappear, but I think if this truely is the Last Crusade, why not? Bring them all back, it'll be a big Indy reunion!