2- I am sure that a lot of people would implement procedures libraries if they could use something like JavaScript or PHP. If we could use Python, stuff like NumPy and SciPy could be used.
Run a language inside database is something very interesting, normally it's done with daemon plugin, but the language c++/c is something that just someguys can do, numpy/scipy/machinelearning algorithms could runs inside server, that's very interesting...