> Debian's definition of stable is rather out dated. By locking down the version you don't increase stability, you just lock in the current instability.

You are neglecting to consider libraries and tools. If you use certain python libraries (or puppet, or C++ libraries, or ... anything?), for instance, you are likely to be severely disappointed when you are forced to rewrite your code (or maybe just recompile it) due to a routine update.

Maintaining API and ABI stability is hard, and Debian stable's approach to stability is one of the few (only?) that can actually avoid unanticipated work to fix breakages across the ecosystem. Everyone has a different set of packages that they can't handle changing without a major effort, and the only "stable" solution is to avoid changing any of them (more than is needed for security fixes).