Let's skip personal preferences for pre-2.6 UI and proceed to actual problems.
Fuzzy overlay that covers everything, making some things too blurry, could be easily disabled, if dev team agrees to remove it. Transition from SDL1.2 to SDL2 also contributed to text blurriness as (*) it has different text rendering (*).
As for poorly chosen colors: as one who contributed to UI2 development, I'd like to hear not only complains but suggestions too. I could implement any reasonable suggestion, but with my dreadful sense of color it's hard to find an apropriate eye-candy color that will please everyone. Do a little research and show results here, if your option is better than default one it will be implemented in no time (in fact, as soon as I visit the forum
).
(*): Controversial info, I'm not really sure. I've done some tests with both SDL versions and I clearly saw the difference. Maybe it's only my problem, maybe it's common for everyone.