Even if it means sacrificing other stuff like stages, music, items and bosses? i was asking this way mainly because i seriously outside of poochy, can't think of an exciting or charming Yoshi rep. If you obviously ask if a fan of a franchise would gladyl take another playable character for free they will always say yes. Mario fans will say yes to, toad, then waluigi, then paper mario, then koopatropa, then king boo, then petey piranna, then goomba, then those weird spider like creatures that floated on the water in mario 64, then etc...
but if you start asking, a mario fan if they will be willing to sacrifice say, half of teh remixes for toad? obviously a lot would say yes, and you can see that toad does hold some value... but they you ask the same question, would you sacrifice half of mario remixes for goomba? and i'm pretty sure the answers would be very different... meaning that people don't really want goomba that much (shocking)
But personally outside of poochy, and thats a big if. i wouldn't cut yoshi content for a playable character.. regarding metroid... i would have cut half of metroid content for Ridley... but now i don't think i would even cut metroid assist trophies for say... sylux.. so while i can entertain the novelty of a playable Sylux, and probably would use him sometimes if given free... is not really valuable to me.
I would actually enjoy teh idea of an unique playable dixie for example,if she just popped in the roster... but if I start cutting DK country to get her, i can see that i really don't need her that much.
On the other hand i would gladly cut Fire emblem content for fire emblem characters.. so i understand that there is a couple of fire emblem character that i really would love to see, same with castlevania and believe me I LOVE Castlevania content in smash... this is obvious subjective but i think is a good way to measure how much one really want a particular character (obviously you need to cut content you actually love) so which character of yoshi franchise you are willing to make huge "yoshi sacrifices" to get?
(PD: Boshi is not a yoshi character DX)