>>6
I think the use of object-oriented design for GUI systems needs to end. Yes, it makes it simple for novice programmers, but at the cost of serializing everything.
GUI libraries need to move more towards how modern highly-parallel game engines are structured, using data-oriented design, task-oriented parallelism with concurrent algorithmic skeletons, and functional techniques like actors/monads.
The free lunch is over, and GUI library developers are straggling way, way behind every other type of developer at adopting concurrent programming practices.