Let the main module provide an alter hook, instead of a normal one

Definitely yes. Should be deprecated in 2.x to reduce the risk of updaters and other contrib modules to miss the update!
https://drupalize.me/tutorial/what-deprecated-code

Done, don't really like the removing of the presave hook in the submodule. Feels worse than before, but please review.

Done, don't really like the removing of the presave hook in the submodule. Feels worse than before, but please review.

But makes order and logics more clear. Less magic, clear flow.

@Grevil: commented, I think we had a misunderstanding regarding the new alter hooks use and logic. See the comments.

All done, please review!

All fine for 2.x! We should now add version information on the module page and inform about the hook deprecation there (and in readme?)
Super nice improvements!

Perfect!

Automatically closed - issue fixed for 2 weeks with no activity.