I've been reading GameFAQs discourse threads on the Smash DLC stages, and one really interesting point I saw bought up in the sea of "why don't competitive players just use Omega and Battlefield forms?" was that, because of how quickly Nintendo's online capabilities expanded between the Wii and 3DS, 3DS/Wii U were the first games where the devs would have hard data on which stages are most popular, and because competitive players have a smaller pool of stages, the competitive stages would far outweigh the non-Temple casual stages in quantity of playtime.