Yeah totally agree with you. Arms was made instead of a Mario Kart 9. Obviously Nintendo doesn't expect Arms to sell MK numbers, but they probably want it to do more than 1 million.
I hope its a success and has huge legs since its pretty damn fun. I am worried about the huge learning curve though since aiming arms, and just getting used to the perspective is really hard, atleast to me. But I've gotten better in my 22 hours of play time.
They also need to add some QOL stuff to it like detailed stat tracking like in Smash, and especially a option to play online party mode in only the mode you want like doubles or VS boss since its such a drag playing modes you don't want, especially when its 1VS1 which if I wanyed to play, I would play ranked.
But overall really have enjoyed it and the overall impression from people that own the game are good. Lets hope it keeps selling and has a long life with DLC and eventual sequels!