MAKEMAKER HAS TO DIE!
Just because you say so doesn't make it necessarily so. There is one central rule to unhappy customers:
Customers don't complain, customers switch
and, in the case of Module::Build, the customers won't switch, they will stay with the proven solution that works.
I am cpantesting Module::Build and have shaken out some bugs tat were present even in the unixish versions - I'm not really convinced that Module::Build is the future, even if MM::EU is doomed. For example, in the current version (0.2605), Module::Build refuses to upgrade itself unattended (should be fixed by now, as the bug has been reported). I'm not really interested in the metaphysical intricacies of building a module that builds other modules, and my involvement with Module::Build should be seen as damage control rather than active interest. If Module::Build goes into the core with 5.10 in its current state, I see a bleak future for Perl, as CPAN loses a lot of its functionality/convenience. Of course, 5.10 is far away, so the statement can still be valid, much in the same sense the Green Party long lobbied for a price of 10 DEM for the liter gasoline, and just after they dropped that point, the price of gasoline skyrocketed to now 1.2 EUR per liter and is still on the rise, wihtout any inside political intervention.
I can set up a special automated Win32 smoketest mailaccount for you, but I won't join the MakeMaker mailing lists, as MakeMaker mostly works on Win32, and works lots better than Module::Build. I can also spend time to diagnose test failures, but I'm not really interested in actively writing code that never gets applied (like, say, for Test::Inline).
Update: I'm a stupid moron - my patch to Test::Inline got applied about a year ago and I never noticed.