More levels won't make it a better game. Act III late game is already falling apart and they are introducing nonsense mechanics like Unstoppable that just break the rules in a bad way. A massive power spike with items that makes previous advancement feel redundant.
And the biggest offender that made me stop playing: level 11-12 spellcasters feel really lackluster. At a time when they should start to feel really powerful with 6th level spells. Because of all the goodies martial classes get, combat is just about dishing absurd amounts of damage on martial classes, stacking all kinds of elemental and radiant bonuses, Illithid powers, and hacking away with reckless abandon. Smart D&D play where magic is powerful, smart, tactical and limited, does not exist here.
Slowing down the leveling would make it a better game. As would toning down the magic items, and introducing some form of actual limitations on how often you can Long Rest.
