What I like about your project is that I've always felt that debuggers and such give us the same 'von Neumann' view of running programmers that we feel our CPU has. It's a bit like trying to figure out why your car won't start when all you have is a view through a microscope. And besides that, it is quite often that which is not happening that is indicative of an issue and debuggers usually allow you to focus only very well on everything that does happen.