We have discussed the idea of squashing migrations. And came to the preliminar conclusion, that we may be able to squash migrations once per project, but will never be able to delete squashed migrations, as that will break some upgrade paths.
Sadly django does not (yet?) support squashing squashed migrations. 
So the current working idea is that we want to take the advantage of a big squashed migration now and maybe never do it again. This builds on the perception, that we have had a lot of erring our ways in the early days of Pulpcore 3.Y and that new migrations are becoming increasingly rare.
The discussion has been captured here: