The Azure API is much more complex that any other providers: implementing it without introducing a dependency on the Azure Python SDK [1] is going to be complex. Just have a look at its source code (e.g. [2] and [3]) to get an idea.
All drivers available in Apache Libcloud have been implemented without introducing a dependency on a custom SDK. Why make an exception for Azure? Note that the complexity does not come from the Azure Python client API but rather from the Azure REST API that is in my opinion much more complicated that any other provider's.
Azure has some specific idiosyncrasies (such as deployments, certificates management, VM images that first need to be transferred to a blob container) that make it harder to fit in the simple and unified Libcloud API.
Also some less-known providers such as Brightbox decided to contribute directly to Apache Libcloud rather than writing there own custom Python client SDK.
Someone working on or using Azure would be more than welcomed to implement support for Azure drivers. Contributions typically come from the providers themselves, or the users of those providers.
Oddly enough, Apache and MS have a pretty good relationship nowadays. There was definitely tension in the past, but MS is a very different company today then it was in the 90's, early 00's.
I wouldn't be surprised, now that it is highlighted, to see MS submit a patch to libcloud with what is needed to support Azure.
