Thanks for all your replies, never thought I would get so much input
I have been thinking again, and it seems that my UI problem is more of a design/UX one, then a straight Addon problem. Like all of you, I used not only ElvUI but also made some UIs myself.
Maybe I should compare good UIs in video games (especially RPGs, not just MMOs) and note what I like and dislike; could be a strategy that helps.