Many Linux users probably don't want to see a single model. They like the choice of being able to choose from different distributions and their own desktop model.

Ubuntu is probably the closest to being a consistent desktop environment and look how much grief they get from some Linux users over their UX choices. The open source model works for software, but it can't work for UX or design (at least I'm not convinced it can) because you can't design by commitee - any yet everyone wants a say in the UX.

Would it have been better for Munich to have specified open document or data formats rather than the choice of software? This is what the UK government has recently done [1]. The choice of software is up to the individual departments as long as the software can read or create the open formats etc. At least this gives you the choice of switching to dfferent software without being tied to a single vendor's closed-sorce document format.

[1] http://blogs.computerworlduk.com/open-enterprise/2014/07/hug...