I like the concept of Athletics and Acrobatics Disadvantage from bulkier armor and it should affect your Jumping ability in combat. A naked Barbarian should be able to jump much more effectively than a Knight in Full Plate.
I'd also like the next edition of DnD to be more dynamic with the Dex bonuses from armor. There's basically only 1 viable top of the class armor from each weight category, and more variety to fit a different niche would be nice. What if Studded Leather was max Dex +5, but Leather was +6. And perhaps Elves and Halflings could have a max Dex score of 22, so high level Rogues would have some armor diversity.
