I think you’re looking at this the wrong way… You need to think of each hero’s suggested power as “potential” power. Or correlate the power level to the potential value of that hero… A 1/1 4* like Chao is way more valuable than a maxed Layla. A maxed Layla power will never be more than 327, whereas a basic Chao is at least as valuable as a maxed Layla because his potential is light years away from that Layla’s. Granted, at this stage it’s untapped power as he hasn’t been leveled up at all.
The hero power is also more of a strategic power value, not just brute strength. Take Zeline for instance, she’s one of the highest (Maybe only second to Alby) powered hero in the game. Sure, there are many other heroes that inflict way more damage, but that’s really all they have going for. Zeline’s ability to severely cripple an entire defense is second to none. Strategically speaking that can mean the difference between losing or winning a battle. Very few other heroes can help determine the outcome of things. That’s what makes her so valuable.
I still see no issue with this sort of grading.
Playing from my son’s account, I see more and more novice players with barely fed 4s and 5s heroes. I think they’re doing themselves a disservice by acquiring and starting to feed these heroes vs maxing out a full roster of 3s… On paper, all those 4s and 5s are of equal or greater value as any maxed 3s simply because of their potential and overall game value, and I’m ok with them being grated as such. If they chose to start feeding those 4s or 5s before they have a full deck of maxed 3*s that’s on them. Chalk it up to life lessons…