>>32801053The design is fine as it is. Most of the people who have it as one of their favorites probably wouldn't like it as much if it was more neutral, and the ones who don't like it have enough other Pokemon to choose from, so it's not a big deal.
Think of how badly received are some sequels in videogame series that try to appeal to a wider audience/everybody while forgetting what the actual fans liked about them in the first place, it would be the same situation.
I haven't played the main game of Sun/Moon with any other starter so I don't know if the Sea Lion makes the game easier compared to them, but it definitely felt like Popplio/Brionne/Primarina could pretty much take on everything in the game by themselves; Lurantis is the only exception, and even then if you can take advantage of Acrobatics and Lurantis' Mental Herb is gone, Brionne can do work.
I'm choosing Popplio again for sure in my run of Ultra Sun, I just can't imagine playing my first run of it any other way.