To my mind, that's much more tenable than the idea that some characters get built one way and others (humanoids) a different way.
I had sort of assumed that was what was being proposed with the Monster/NPC divide and thought that much superior personally. The obvious problem is that it requires a separate and significantly better detailed system to evaluate CR. It simply isn't sufficient use those inputs by themselves to archive at a meaningful difficulty analysis, but that problem doesn't really differ that significantly from 5e anyway.
Honestly, I don't actually think the basic math derivations for attack bonuses/skills/saves were as complicated as they get demonized to be. You're mostly doing 1/2, 1/3 or 3/4 of hit dice, maybe with a +2 modifier. If you ditched cross class skills or used the pathfinder level+3 system and we're just selecting skills to maximize, it's a calculation you get pretty quickly to memorizing.
The issues were spells and feats. That's a space where some sort of standardized templates that let you go from feats to final numbers or standardized load outs by monster role would have been a sensible norm.
I have less sympathy for people who don't want to internalize the spell list or look up spells at the table. Some reprinting of spell effects in monster writeups is fine, but in general that's a price I'm happy to pay for a consistent magic system, and spell-like abilities largely made that easier and more consistent, not less so. Eventually you know what
animate dead does, and it's easier to write that than 7 different species specific undead creation powers, while also reserving the option to write a weird species specific undead creation power if you want.
Fundamentally, I don't think the problems were systemic in the way they get described. It was specific implementation, things like Wild Shape and summoning spells, CR and the expected encounters/day, not the underlying unified design.