I would like a feature request like JEI has where you can specify make UI larger by width or height, so you can reduce the amount of scroll bars. And make it look slimmer, like on attached picture the buttons would move to the right hand side when this was made wide enough. And would liek to make it longer to easily see more.

Related to MineColonies, Domom (what eer that mod is called)

Same with the postbox, Architechs cutter

DO (domum orn.) is using vanilla system (not blockui), you would have to repost the issue there
But generally speaking: our UIs are rather complex, I guess we would have to specify such behaviour for every list we have (or for every we decide it is worth such feature). Leaving this open for comments, but I don't think it's easily doable

Ingame screenscale should allow most UIs to be larger