Apparently a lot of developers are pushing for their small-name characters like Shovel Knight and Shantae to be in Smash 4. K. Rool obviously deserves to be in it over them, but that was the case for a lot of other newcomers to Smash 4. I don't have anything against these characters but if any of them got in while big-shot K. Rool didn't, I would be sad. Unfortunately, Sakurai would probably consider them before K. Rool if the whole "relevance" thing is real. Come on, is K. Rool too much to ask? Just one little K. Rool is all I need. Just give me that and I can love again.
While I can agree with Shovel Knight being young, pairing Shantae with him is a bit much.. I'd like to present a bit of backstory, if you guys wouldn't mind ^_^
Her "obscurity", as many like to pull against her is primarily bad luck in her beginnings.. Her first game released on Gameboy Color in 2002.. which of course was near the end of the handheld's life. That caused the game to see a limited release.
In fact, after that game She wouldn't see a sequel for eight years.. quite sad and needless to be honest.
She has 3 games under her belt so far, with a 4th, Wii U exclusive one, dubbed "Half-Genie Hero" in the works too. 99% of these titles released exclusively on Nintendo consoles (Risky's Revenge being the only exception. While debuting for the DSiWare, it later received ports for iOS and Steam) Even despite that, she is actually "barely" indie.. Her series is quite dedicated to Nintendo for being considered indie by today's standards. She also has a fairly big moveset pool that can be pulled from the three titles
Also, while not having been released in Japan, she has a cult following there as well... The fans over there desperately want the series to be localized. So, she is anything but small, like the one year old Shovel Knight (I'm serious actually. The game is literally a year old XD)
And to be honest with you... King K. would be considered more "relevant" than Shantae is, by everyone's standards. I mean he is the biggest villain in the DKC series, has loads of moveset potential, and has a huge fan following.
Even with this I hardly see relevance as an issue in all this. Look at the ice climbers for example. They were probably as obscure as you could get back in their debut in Melee, and Sakurai added them.. Speaking of Melee, remember Fire Emblem? Smash practically helped get that series localized out of Japan to begin with..
To be honest, I'd be more peeved if the likes of Cat Mario got in -_-