R. Mika was only in one other SF game, Street Fighter Alpha 3. Nobody played her and she wasn't good, however, it became trendy to bombard Capcom with requests to put her in SF5. Most people playing SF games these days wasn't old enough to take SFA3 with any seriousness. However, these players continually tweeted and posted on forums for years for R Mika to come back so now she's in SF5. Realistically, she was only wanted in the game for two reasons: sex appeal, and weirdness factor. The sex appeal is pretty easy to explain; there's a girl in a thong who hits people with her ass. The weirdness factor is a bit harder to explain. Pick an odd-man-out and unloved character to give yourself insta cred and then pretend (and pretend loudly online) that this is a character that you would definitely main.
It's the same reason that people want Q in SF5; he's an unpopular character that was bad in the only SF game he ever appeared in. Only one guy in the world used him and this guy happens to be the strongest player of SF3 with about half of the characters in the cast. There were never hordes of Q players but he had a weird gimmick allowing him to get tons more life and it was easy to do meaning people thought they understood how to play him. However, after getting the hit points, what's next? Nothing, Q's offense sucks and the other player will likely slowly whittle away at your larger life pool. People who actually play these games don't care about Q because why should they? All that being the case, only a TRUE street fighter fan would want to play the character, RIGHT!? Therefore if you claim you want Q on the roster then that proves TO THE WORLD that you really know your stuff!
Back to the topic at hand, however, R Mika has a large portion of her current popularity specifically due to her sex appeal. I'm positive that Capcom knows this and the only reason I can fathom for them to remove it is due to the potential concern of getting rated M or whatever rather than T. If that's the case, and Capcom feels that the T rating is more important for sales than added sex appeal, then fine, take out an ass slap or a camera shot panning up behind Cammy's thong (not that said camera shot stopped SF4 from being rated T).
...yes, there was one specific time during B4 when R Mika was selected as a dumb counter pick in the finals and she lost anyway accomplishing nothing more than landing 3 tick 720 supers. Anyway, I'm at least a bit curious if this podcast will complain about DoA Volleyball 3 not receiving a US release.