Update: In Theory (or as I like to put it, theINory) we now have 2 AntiSpam modules in place that should alleviate the burden.
They don't (yet) affect the registration process, but should help out against payload posts and the like. The reason why it won't yet touch on the registration process is because that is a little more convoluted and has a significantly larger amount of edits and things that could go wrong as a result. I do have it staged to activate however.
I'm also thinking about a potential idea. Restrict User Pages from being available until 'X' contributions. Thoughts?