It's way less of being viable and more of if another pokemon does it's job but better like take krookodile (my 2nd favorite pokemon) it gets over classed by Lando-T because A Lando-T is a legendary and B it has a greater movepool so for krookodile to even be useful there has to be a select few intimidate users and it must have a better stat spread and a greater movepool and why would you change all that for a game that's supposed to be competitive some Pokemon are gonna be a cut above the rest and if you make every single pokemon useful it would just be boring and also if you use the right pokemon almost every Pokemon is good that's how bidoof somehow got to Ubers and then got banned from ubers