Hey Meddler, want to discuss a dancer Champion?
You might have noticed this one I've been putting together here: http://boards.na.leagueoflegends.com/en/c/fancreations/krgIgak5-yousoconcept-freesia-the-spirit-dancer
The idea of it is that not too many dedicated supports are highly mobile and meant to dart around fights rapidly. It might seem more an assassin thing, but who said supports can't do it? Braum has the ability to jump to teammates, yes, but I wanted to take the idea further.
That, and we don't have a Champion who uses rhythm and dancing movements as a means of fighting/supporting. Dance emotes and Orianna don't count.
Precedence in gaming? Fire Emblem series. The dancers in those ones are purely supportive. There are other examples, though not off the top of my head.
Precedence in MOBAs? Chang'e from SMITE.
Ideal kit? Well, everyone has a different opinion, but mine is that of a highly mobile, short-ranged Champion who is meant to take a lot of risks, move from player to player rapidly, and both enhance allied movement and trip up enemy movement. This does not necessarily mean locking down an opponent; this means making them "stumble", just long enough for someone to finish them off. Standing back or playing passive, though? NO WAY!
Inspiration? A number of sources, but one in particular is the Shantae series. Gives off the kind of "Arabic" vibe I'd like this dancer to have, since she'd originate from Shurima. (Heck, what happened to that Shurima patch?)
More? I'll add more if people ask. In the meantime, though, what do you think? Want to see a "Dance through the Danger" type Champion at some point?
, Pop-Star 
) a dedicated dance champion could be really fun to mess around with especially for the art team as there is so many sources of inspiration they could pull from. Having something like different skins result in different dance animations respective to that culture or something to that effect.
(my favorite support) but thats not so much mobility as it is her high MS she gets from her W. I could see a champion like this going well with Marksmen like 
and 
who's mobility could synergize together in some ways that would be fun and make room for some awesome plays but would require some serious coordination between ADC and support. Also it seems she would want to stay at a distance so champions such as 
and 
would be able to wreck her if she gets too close and stops moving. So then there is a clear counter to her but also room for outplay.
or 
have quick bursts of speed, this would have to be a slower but more consistent flow. It also seems like a champion that would have a high skill cap which I am all for. Other than that I could see finding a way to keep the dancing identity tied in with passive animations being a problem but not impossible.