I don't really care either way about the colors and the fonts. I care more about functionality, and the current version still has a very annoying bug, where there's a type of spam email that Thunderbird will choke on when trying to download it using POP. I have to use webmail to go manually delete the offending email so that Thunderbird can download the rest of the emails. Last time I investigated this, it seems that others have reported this problem, but nothing's been done about it. I'm very close to moving to Outlook now (which would also help with calendaring, but that's a whole other can of worms), and a simple re-design isn't what's going to keep me as a Thunderbird user.