"Rewrite the whole system" is generally a BAD idea. You might want to have one or two senior guys go and prototype the core parts of the new .NET version. You c

"Rewrite the whole system" is generally a BAD idea. You might want to have one or two senior guys go and prototype the core parts of the new .NET version. You can then add resources to the new one as it progresses. In a lot of cases the development of the new one can overtake the developed-in-parallel old one if it's done well, since they don't have to work with all the overhead of the old legacy junk. And if the new development project fails, oh well, you only sunk a few man-months into the failed project. The sunk cost is smaller, so it's easier to abandon.