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.
We're clearly playing different games.

Which kinda shows that a game so big and rich will always fall short in one thing or another. And through the many optirons provide possibilities and exploits which -- unfortunately -- may make the game less interesting or challenging if you choose to use them.
I agree with the observation that there are too many crazy magical items. It''s like the failed homework from magic school that got dumped in crates and barrels and forgotten in old cellars. But I choose the one I find coolest and sell the rest, or send them to camp to empty the box, but I don't change gear according to the situation. (Like get some armour against undead when you know there are uindead and then change it to armour against fire when you know there's an opponent using fire attacks...) My PC ( a Drow) carries Phalar Aluve, and though I can equip with weapons that do more damage per attack, I just keep this sword 'cause I find it supercool.
What I don't like and don't understand in certain comments are requests like 'limit the number of long rests". This is completely in your own hands. You rest when you want. The game never tells you when to rest. So why would a player want to dictate how other players must play this game ?
I rest very often. And not only for replenishing spells and hitpoints. Also for, well , just to rest. Get out of the danger. Talk to the others, even if they tell me the same thing as last time. Admire my wonderful character while reflecting what I will do next, while sitting in a quiet spot.