If I were Sun right now, I'd freeze ANY work on anything other than 5.1 and actually get it released. I'd maintain the freeze on anything else for 3 months to ensure that 5.1 bugs that crop up are nailed quickly and during that time I'd be having a lot of strategy discussions about where MySQL is going and why ... and then I'd streamline the development so that they're focussing on one problem at a time - and not dozens.
It all smells a bit like FFMPEG, a truly great (potential) video decoding / encoding engine that is ruined by poor project management and the inability of the group to focus on fixing bugs instead on building codecs that no-one really needs. Heck they don't even do formal releases now and have basically given up on any degree of control. It's a crying shame, if those in charge got together and said, right, for the next 6 months we implement no new features, we just concentrate on making what we have now work properly, they would have one of the best open source projects on the web - as it is, FFMPEG seems doomed to wallow in the backwaters of things that are great for hobbyists, but of little use elsewhere.