The creators were in constant touch with GRRM. They knew where he intends to go. The ending we got could be done better if things were fleshed out over a longer period of time.
We know he has a specific destination in mind. It’s well established that he had an outline for what was originally a trilogy. It’s why the first book is heavier with hints of (for example) Jon’s lineage than the others.
How to get there has clearly changed, and GRRM might not know how anymore.
The only problem is that GoT didn’t have any more source material, as Martin didn’t finish the story (think he still hasn’t?).
The creators were in constant touch with GRRM. They knew where he intends to go. The ending we got could be done better if things were fleshed out over a longer period of time.
You’re assuming GRRM knows where he intends to go. Or more importantly, how he intends to get there.
We know he has a specific destination in mind. It’s well established that he had an outline for what was originally a trilogy. It’s why the first book is heavier with hints of (for example) Jon’s lineage than the others.
How to get there has clearly changed, and GRRM might not know how anymore.