People said TWWHD was one of Nintendo's "Big Guns" for raking in some profit.
What possible future games would be a "Big Gun" and be a massive money maker? Be creative.
Here's a few that would take in some serious profit:
-Super Mario 64 Sequel (or HD remake)
-Earthbound Remake (or actual Mother 4)
-Ice Climbers reboot
-Yoshi's Story reboot(which is coming for 3DS)