I was fine with the aliens as well. People who complain that aliens are not appropriate in an Indy movie don't realize that the Indy movies are meant to pay homage to films of the past, silly or not.
I didn't mind the alien aspect, which seemed to turn a lot of people off. Lucas and Speilberg were just paying homage to 50s B movies and Graham Hancock (Fingerprints of the Gods) and Erich Von Daniken (Chariots of the Gods).
I'd like to see Sallah again. Marion for sure as well, Oxley could be good too.
Here's hoping they do a great job with Indy 5. I hope to see some characters return like Short Round, Jock, and Sallah. I wouldn't mind seeing Oxley return and give him a better role than being a "stoned hippy" throughout the movie.:))