Agreed about the abstraction. In my view it works best when the abstraction is related to higher-level concepts that are implemented on top of the different clouds, like e.g. self-service, events and automation. This is where ManageIQ focuses.

Abstracting at the same level, while useful and provided by ManageIQ, gets into the "lowest common denominator vs cloud specific APIs" trade off. This is where libraries like e.g. Fog play.