Don't know if they would play Rush songs w/out Neil, but I could see them making more original music. Geddy said now that his Big Book of Bass is completed and he's about done promoting it and doing book signing, he is interested in making some music again.
Knowing now that Neil had been battling cancer for the last 3.5 years, it totally make sense that whenever anyone asked Geddy or Alex about the possibility of playing again with Neil, they flat out said there is no chance, Neil is done, retired, he wants to spend time with his family now. Dude was dying of cancer...of course he just wanted to be with his family, wife and young daughter.