So after seeing my therapist and doing some deep introspection during my daily meditations, I have to say I’m onboard with this idea. But there are a few caveats and suggestions:
I would rename your thread title to remove the word “default”, as it suggests changing the default behavior of the installer.
This is partially true, as it depends on how the user’s PC was partitioned “out-of-the-box”. I don’t know for sure, but what if some PCs ship with a hefty 256MB or 512MB EFI system partition? Would resizing it make Windows complain? I haven’t played around with that before.
I think the idea is great, but not as a “default” behavior. Using the existing EFI system partition has done well for the installer, and so to stray away from this as the default might not be worth the risk of unforeseen issues during/after installation.