Y'all need to chill. I don't see how any of those are bad choices with and without the context of their move sets.
RosaLuma represents the highest point in the already legendary Mario series to date, gives some female player character diversity to the roster and comes with the unique Stand mechanics.
Greninja's
a poster child of Pokemon X/Y and comes with a slew of well realized actions and animations while fitting it's theme admirably.
Wii Fit Trainer fits Sakurai's quirky character quota and fits in the roster the same way that Mr. Game & Watch or R.O.B. do by highlighting the alternative or expanded universe of Nintendo's development history and hardware.
Miis were GUARANTEED to be in this both for what they mean in a similar light to Wii Fit Trainer, and for being the first real attempts at making player avatars a reality in Smash. Also, contrary to what a lot of people feel about them on message boards, Miis are one of the most iconic things about Nintendo in the last two generations.
Fire Emblem is a big boy franchise now. Awakening's popularity allows it to have a resurgence among public opinion and as such, Nintendo's going to take full advantage of this. That said, Robin was an
excellent addition and way better than the large majority of characters who were being championed for getting FE up to the three character bracket. By finally focusing on game play aspects of FE and playing the character up as more than "Lord with Sword", Robin was automatically the best thing to happen as a newcomer from the franchise. Lucina was a coincidental surprise that appeals to the same group and while I myself have no love for her over the much better Robin, the fans of Awakening got something a little extra and that's cool.
Dark Pit is about the "worst" it gets and even he makes sense given that he's popular, his move set is different enough from Pit's and it still adds more than it "takes away" in the eyes of people who are concerned about their picks who had no work done on them being drowned out by the inclusions of bonus psuedo clones that exist because "hey we have values and assets we can play with, wanna give more characters to people?"
Admittedly, I wish if Viridi or Medusa had been cloned off of Palutena over getting Dark Pit though just because I'd love more takes on Palutena's move set. If she's "tanky offense", I'd love to have seen glass cannon.
As a side note since I'm feeling particularly rant-y and catty, this notion that certain franchises shouldn't have X many reps or X many reps more than Y franchise is dumb as fuck SmashGAF.
Haha, I defintely remember retweeting that the moment Bowser Jr got in with Koopaling alts confirmed.