Interesting idea. WordPress sort of does it by having a new template each year, but that's only for the front-end. MediaWiki does same to a lesser extent (new default template much less often) and greater (there isn't really a separate admin UI). I used to think FLOSS projects breaking UI in name of innovation/improvement/progress was mostly a good trend, another thing that received wisdom being that FLOSS can't do, that would be proved wrong. I'm less sure now, that redesign is a good thing, almost ever, for both desktop programs and websites. It is very hard to objectively discern improvement, and trivial to waste massive energy debating gut feelings. I long wondered how some super prominent sites with lots of money on the line could be so seemingly horrible (eg ebay, amazon, dell) but maybe they know something. I can kind of pinpoint when my opinion tilted -- libreplanet 2012 when a presentation about GNOME3 mentioned that it was catching up in accessibility to where GNOME2 was. I was never really sympathetic to all the complaining about GNOME3 til that moment. Not because accessibility is the very most important thing for me, but it's an indicator. This of course isn't specific to FLOSS at all; MSFT has been paying for making wanton changes over and over the last several years.