
In a recent interview with Japanese newspaper Nintendo Dream, Splatoon director Yusuke Amano explained why the game features 2-map rotational design when playing multiplayer.

Nintendo has recently restored Wii U Mario Kart 8 and Splatoon online after five months of being offline.

Game Rant Writes "Mar10 Day is a fun yearly celebration of the Super Mario series, and Splatoon may warrant a fan-designated day of celebration in its own right."

How, exactly, did Splatoon reach heights rivalled only by Pokémon in Japan? New IPs from the House of Mario appear as often as shiny Pocket Monsters, yet typically move comparatively mediocre numbers or fall into relative obscurity behind the premium marques of Mario, Animal Crossing, Zelda, and Pokémon. Take Pikmin and ARMS, for example, which we adore but struggle to compete with the tentpole franchises when it comes to sales numbers or mainstream mindshare.
So, again, how has Splatoon risen to become one of Nintendo's most important series in Japan?
That's a pretty nonsensical explanation because the "if we rotated all maps people would chose the common divisor" (weapon most effective across all) would only be an issue because you cannot change loadout as you line-up for a game.
If you could select your gun at the start of a match then people could chose based on the map in question and there would not be the 'common divisor' selected across all. The issue is that you cannot select your gun between matches, and this issue is not only inconvenient for those that want to switch weapon without backing out of a lobby but something that has seemingly additional poor design choices like the presence of map rotation.
LOVE Splatoon ... but the limited to 2 maps per mode rotation sucks.