...Or is it another case of delayed updates? I for one hope that it is as Crate has been good so far with the updates so far!

The definitive edition...

EDIT: Answered my own question!

These are Steam propaganda:
Often these "complete", "definitive", are lies so you buy all that Steam have. These are Steam words, not dev words.
Soon you'll discover this was not complete or definitive, as some other DLCs can happen.

Sure, devs are not nice if they let Steam say what they want.

Well, it's pretty clear that, apart from a few more updates - the content of which has yet to be specified - GD's development is winding down. So yes, it's a definitive edition because there won't be anything more to come.

From what Zantai said in a couple of dev streams, it's Medierra decision on whether a bundle for the game would come out so not Steam's. He also said in that linked reply "on Steam you can purchase a bundle partially if you already own parts of it". Plus the various parts are on sale on Steam anyway atm until the 3rd December.

So is it coming to GOG or not?

It is a matter of time before it comes to GOG. I am a patient man. I can wait

I've already bought the game, the 2 expansions and both bonus DLC's. Probably have the "definitve version" already.

Yes all is already here, I already have this DefEd here, it will give no new nor more.