Lil Mac and the Wii Fitness instructor, I am pretty disappointed. These are not characters that I have explored worlds with throughout my childhood. They take the fantasy element out of the games. They are just generic and non-inventive characters. There are SO many characters that would add charm to the game in place of those two.
This is absolute bullcrap and would only lead to a generic roster.
By your logic, we should take out Marth, Peach, Donkey Kong, Link (there's really nothing fantastical about him), Snake, etc because they have nothing fantastical in their moveset. Hell, take out Mario and Luigi's fireball, and they're pretty generic too.
Lil Mac and WFT add variety. The fact Little Mac is realistic alone is what makes him stand out, and Smash despite being a fighting game has a lack of an actual martial artist, and the best character to fill that void is the one classical character that they should have included long ago called Little Mac. Wii Fit Trainer is a hilarious character that is cleverly designed around the usage of exercises.
Your perspective of lack of creativity and genericness is flawed. If the character doesn't have fire powers, or if they can't fly, they're automatically generic? You really need to realize that's really not how it is. If anything, out of all the newcomers, Lil Mac and WFT look the most creative and fun. What they lack in gimmicks (Rosalina, Mega Man) they make up for it with proper representation of what they're based on. They used their limitations in their design to creatively pull a moveset that easily fits in line with the series, whereas it's SO easy to make a moveset for Rosalina and Mega Man if you wanted gimmicks. They're also not realistic. Take it from a boxer, you won't find a boxer who has a style like Lil Mac. If anything he's straight up anime.
Out of all the newcomers revealed so far, Little Mac deserved it the most. Not being biased, but he has the least detractors AND he's actually iconic, not to mention he also adds ACTUAL variety to the roster.
Seems like you're judging them based on their aesthetic design ("get that generic human **** out of my smash bros waaaah") over their function. There's your problem.