I’ve seen this suggested before but it doesn’t address something that blizzard themselves have said was a motivation for the 60-squish: Empty levels. They want more dings (it might even be every or every other) from 10-50 to gain something substantial and permanent whether it’s a new ability, talent, a flight level or a feature like lfd, and (as I interpret it) they’ve done that arrangement now for the potentially evergreen 10-50 to hold it forever.
Yes, the math for the Chromie time bracket is, I’m sure, flexible, but the number of systemically relevant and permanent gains-per-ding is much less so.