I really enjoy classic and the fantastic feel to the leveling experience and all the things you mentioned.
That said I just don’t think it’s sustainable in a game for 20 years and 9 expansions worth of level cap raising.
I think the scaling could be done better to make the mobs feel like they have the slightest bit of teeth and you’re actually engaging with an enemy instead of a loot piñata, but going back to how it was in vanilla I think would be a bad change for retail.