Module::Build will not get my support until there's a replacement for h2xs -AXn Module::Name that builds the templates to use Module::Build rather than ExtUtils::MakeMaker.

That's easy enough to fix. I'll try to remember to send the author of ExtUtils::ModuleMaker a patch to support Module::Build. I much prefer eumm to h2xs.

I'm not sure why people believe they can change-out core modules without providing at least as much as what was working in the past. {sigh}

I'm not sure why people believe that a plan to replace a core module doesn't include doing exactly this. In other words, I don't think anyone is planning to throw Module::Build, in its current state, into the core. The goal is to get all the functionality it needs, then put it in the core.