I"d love to see a return to the GBA-style Mario Golf games, but I'm glad World Tour seems to have more to it than the bare-bones Mario Tennis for 3DS. X looks great, but I wish they'd have had more to show. I'm also looking forward to NES Remix 2, as I'm really enjoying the first one.
I never understood why the console versions of Mario Golf had significantly less to do than the handheld ones. Those were so much more interesting with their RPG stories.