Why dont you install bugzilla or something similiar? You will get more accurate bugreports and less duplicates since it's easier to search for similiar bugs.
It's also gr8 for me as a customer to be able to see if the bugs that i've reported are fixed or not.
Probably because Bugzilla is a pain in the a.. to install and use. And it does not do anything good. The system currently in use which refers to topic numbers is pretty useful. And permanent visitors of the forums have a good overview of what is going on here.
As VA is not an open source product, WT team probably doesn't want to expose some of their internal issues. On the other hand, I don't agree with Uniwares that Bugzilla is painful to use, I find it a very versatile issue tracking system, used internally for many of our products.