Instead of the brutal patchsets that simply remove all the features that touch anything from google, it would have been amazing if there was a project that aims to make them pluggable, maybe even to end users, not just during compile time. Being able to switch these features off or even chose a different provider for it would be pretty great I think. Sure, some of the features can be replaced with extensions but not with the same integration.
MicroG (re-implementation & stubs of Google Services for Android) tries to do that at least in some areas, e.g. the location provider: https://github.com/microg/UnifiedNlp