I'm the author of some LDB addons and would like to announce my new non-LDB-addon UI_Tweaks :) In addition, I hope for feedback!
What is UI_Tweaks?
It's a compilation of little or not so little UI improvements. The default UI does a great job, but in my opinion, there are still many niches which need to be filled.
What does UI_Tweaks?
Well, it tweaks your UI. For example, the Blizzard watch frame for quests and achievements is in golden and white colors. It takes me more than 1 second to realize if a quest is done or not - I dislike that. I could install a quest addon with a new quest tracker, but I do not want to do that. This is where UI_Tweaks is in place. It encolors the default Blizzard quest tracker with quest difficulty and progress colors.
There are some other tweaks as well, but I think it's better to visit the addon page:
UI_Tweaks images on Curseforge: http://wow.curseforge.com/addons/itweak/images/
There are many little tweaks planned for the future. Hope you will enjoy!