Correct me if I'm wrong but I think most of the frustration people are having with the percentages is simply that they're there and there are to many things effecting it besides what's normally taken into consideration by most DMs. A percentage is misleading simply because there's almost no explination as to why it's that way. The easiest fix I think would just be to remove the percentages all together cause it really doesn't serve a purpose besides frustrating a player when it seems like a high chance to hit and then missing.
When you're playing D&D it's not like your DM is telling you the AC of the monsters in the first place so there's always that element of the unknown when facing a new monster. A change in the interface that simply shows whether you have Advantage or Disadvantage before attacking, I think, would work better. The little pop out menu that shows the math behind the rolls is nice and for some reason it's easier to handle missing by knowing I rolled a 4 instead of having no info at all but maybe there's a way to communicate that instead of the percentages in an intuitive way. I'm not a UI/UX designer though so I'm not sure what that could look like.
