Starting to wonder that myself. Pretty much every 5* since Shogun has been disappointing in one way or another. They seem overly cautious of balance in a game with literally zero PVP and only one endgame mode.
I always think about it this way too - we're probably the outliers to this stuff. The people that look at numbers and kits and how to squeeze the most out of character. As
BlackM1st
mentioned you have people with no artifacts, no talents leveled, just doing their own thing. So character balance literally means nothing to them. They probably don't even know that Kokomi has negative crit rate, or that shogun scales off of ER. So why cater to the most extreme of the hardcore that would cry if a new DPS was even mildly more powerful than a launch unit?
I've played gachas that have had off the charts level of powercreep (Fire Emblem Heroes), and I've played games that take a lot of consideration to balance (Epic 7), and I can tell you that neither of those two extremes are fun. They should just make characters that are fun to play and not try to pigeon hole them into specific setups like they've been doing for all of Inazuma. Let the people have some god damn fun. I don't want to run a triple Electro team just to get the most out of Yae.