The h-entry microformat covers all the same use cases as schema.org/CreativeWork and is already in place on many sites. I think it would ease adoption to allow these classes to be used instead of (or as well as) the microdata metadata.

It should be fairly straightforward to map h-entry class names to CreativeWork item properties. I'm happy to help out with that mapping (and I'm sure many others in the microformats/indieweb community would be happy to help out too).

Cheers,

Jeremy