No support for threading, no asynchronous primitives.
Poor tool support - no refactoring browser etc...
Poor support for RDF, especially RDF/XML
I am thinking of splitting veudas into a client/server system, using python cgi. I've experimented with PHP, and have gained a little experience with it while coding the RAP joseki net-api, but I much prefer python - specifically its brevity of syntax. I also know bicyclerepairmanback to front ;-)