Would you consider Splatoon a racing game? My girls LOVE this game. It's such a fun game to play and it's fun for them to play with other people. Would you consider it a racing game? Do you play?
Maybe, lots of games with a ton of characters could profit from spin-offs, especially racing games, or even fighting games. I wouldn't mind, as long as the gameplay is good. I honestly don't care if game companies milk their products, as long as each game is innovative, creative, and fun for the fans. Because basically, it's fan service, and fan service is always good if the fans get to see their favorite characters in a different sort of light.
I wouldn't really consider Splatoon a racing game, it's more like a realtime-strategy game that's similar to a MOBA. I guess theoretically you race to get the better percentage but that's about it.