This thread holds true to this day. As far as your ICC boss comment, keep in mind that ICC bosses have more health than BFA mythic bosses. It’s a complete joke and Blizzard does not seem to care at all at this point. No communication from a company I give hundreds to every year is disgusting.
https://us.forums.blizzard.com/en/wow/t/legacy-raid-boss-health-scaling-is-hosed/823633