WF4 was not much of an improvement from WF3 with the exception of various bug fixes. However, WF5 has some significant improvements that would be worth checking out. There also were a lot of improvements in Mechanica in WF5 if you guys use Mechanica. I use the knowledge base a lot to look up issues, but I do know of guys that have never even logged in. With 30 seats maintenance has to be high. Perhaps you can negotiate with PTC more given the size of your maintenance contract.