Indeed. There are custom kernels avaialbe for overclocking, hacks for all sorts of stuff which have been made easy by the fact most of the system is open, with the source available.

None of which means Nokia is or should be under any obligation to release code it doesn't think is finished. Not only is it in a different reputational situation to John Q Hacker, it is probably legally vulnerable as the OEM of the hardware should the firmware it releases cause problems. That's why it has QA processes. It might be nice if it were developing in a more bazaar style fashion, but while it is the design authority that isn't likely for reasons of liability. With meego being at arms length, the situation may change.