Well, TwoSix, reading about the Bounded Accuracy concept behind 5E was what disappoints me. I never found any problem with the idea that a group (even large) of goblins and such should not be any real threat to higher level characters. As characters became more powerful, getting strong magical items went hand-in-hand with getting more powerful spells. Facing stronger foes that would crush lower-level characters was exciting at upper levels. To me such things made the game heroic on a classic scale. The escalator effect, or whatever it is called, was never an issue.
I have been thinking about it this afternoon, and I think an easy fix might be to do something like this:
Hit Dice is d10 or better, use Proficiency Bonus (PB) to Attack rolls, use PB - 2 for Skill Checks.
Hit Dice is d8, use PB -1 for Attack rolls and Skill Checks.
Hit Dice is d6, use PB -2 for Attack rolls, but PB for Skill Checks. For spells requiring an Attack roll, maybe use full PB still... I'll have to think about it.
Saves and other Ability checks use full PB for any type of HD.
But also I like the idea of Armor giving DR instead of increasing AC. It makes more sense. The target is still struck by a weapon, but the armor protects the wearer from the blow, taking all or some of the impact.
Anyway, I could go on and on, but that wasn't the point of the OP. The argument seems to be Fighters are balanced (for the most part) as is and Burning Hands (and similar) won't unbalance things either. But, if you have any suggestions I am listening LOL.