Yeah but then some people wouldn't give a anyways.
Don't worry, I have stockpile.
This if far from the most popular choice, and I'm sure most people are actually against the idea.
However, I see posted occasionally that a Rhythm Heaven representative deserves a spot in the game and I think I agree.
Sure, a stage would fit the series fine, I admit, but I will say that a lot of potential would be wasted to cram the series into a stage.
The biggest problem for Rhythm Heaven isn't the moveset of course, but the character.
Rhythm Heaven doesn't really have a definite main character. There are many choices though.
When it comes down to it, people suggest one of these five:
Karate Joe
Rhythm Girl
Rhythm Monkey
Marshall
Wrestler
Out of these, the only character notable for popularity is Wrestler. However, given his relative unimportance I don't think he has any bit of a chance.
Marshal was the announcer of Rhythm Heaven Fever and was based off of the chorus kids from Rhythm Heaven. This is big because, besides the wrestler, the chorus kids are very recognizable for Rhythm Heaven fans due to their appearance on the boxart of the DS game. Unfortunately, those two roles are all he has in the Rhythm Heaven series and otherwise doesn't have a huge presence in the games.
The most reoccurring character of the list is by far the Rhythm Monkey, appearing in several minigames per game and constantly being featured in graphics advertising or showing off Rhythm Heaven, even having a cameo appearance in Game and Wario. This is where the characters start to get a morsel of a chance, because he's one of very few mainstays in the Rhythm Heaven series. Although, his negative qualities include a relatively bland and unrecognizable look. Other than that, he can share a shred of a shared chance with the next two characters.
Rhythm Girl doesn't appear in very many minigames. In fact, she was only in two which were from the first game, released only in Japan. While for most this would be considered a downside, I'd say it actually improves her chances. While not appearing in many minigames, she has a huge role in marketing the game and appears on the title screen of the second and third games. This kind of omnipresence gives her a chance because she lies outside of the hundreds of other characters in Rhythm Heaven. Maybe not particularly popular or unique in looks, but her stance of being outside of the restrictions of a minigame give her an advantage over most other characters. I've also created an image with a moveset by DonkaFjord. Please take a look.
Karate Joe is the last on the list and in my opinion the most likely. Most people don't know what the hell kind of character Karate Joe is and I don't blame them. In the two localized Rhythm Heaven games he appears in the last minigame of the main game, but in the Japan-only Rhythm Tengoku, he's from the first game you play. He's obviously beloved by the creators because he's appeared in every game since, twice over with two minigames a game. In total he's appeared in 15 out of the 140 minigames of the series due to all the remixes featuring him. Like the Monkey, this is unique among all of the other Rhythm Heaven characters. Something else about him is his monochrome appearance. He's instantly recognizable next to everyone else in the game. Does the white palette appear too similar to Wii Fit Trainer? Maybe, but he can always be his blue coloration by default instead as it's the most common depiction of him anyways. Another thing that puts him ahead of the rest is that he already has a feasible moveset from his own games, and is also a fighter. He's simply an important character to the series and I see him taking the spot before any other Rhythm Heaven character. Also, I've made a moveset for him, please take a look.
Of course, a Rhythm Heaven rep is something that's unlikely in the first place, but it's something I think would be unique and I'd want it to happen.