The great thing about the Django Admin is that - because it was actually part of the Django itself - there is a whole ecosystem of extensions, add-ons, skins etc for it.

Any attempts to replace it for Django would have an uphill struggle for that reason alone.

This is one side-effect of an opinionated framework - the provision of a default choice facilitates cooperation and prevents fragmentation.

(We recently picked up a Pyramid project and I was rather surprised how big the impact was of the extra choice. Simply in terms of searching for answers to questions - we often had to find an answer from someone who was using the same combination of parts that we were using. And figuring out how to do x often fell into the gaps in the docs between two components and was therefore harder to figure out)