Why not ax one of the many craptastic venues that f1 is plagued with.
Seriously though, there are more than a season's worth of F1 tracks that belong in F1 (either for money purposes, racing heritage, fan service), F1 needs to seriously looking into rotating races. Give each region a chance to enjoy the sport, sure, but maybe we only need 2 Middle East races per season, 3 North American etc.
It's not unheard of for certain races to rotate venues. Canada, Germany, Japan, Britain have all used alternating facilities. The European Grand Prix was basically an excuse to put an extra race where F1 could make a few extra $$$ based on the whims of fans.
I'd love Spa to be every season, but having it every other year is fine too. Singapore can swap around with Malaysia. Montreal/Las Vegas/Austin/Miami/(New Jersey? Laguna Seca?) could certainly find a way to share.