How much of the Witcher 3's main story and gameplay elements were fundamentally altered or significantly expanded on post-release? Genuinely curious because I only bought it years after the fact. Whatever the degree was, that's the most we can honestly expect will happen.
They didn't do any major changes to TW3. The biggest being an overhaul of the movement system because that was broken.
I don't think that's necessarily representative in this case. The main complaints about TW3 we're not of the same order. The game needed work but not CP2077 amount of work. CDPR was also a much smaller company. The amount of work they put into CP2077 post launch should be directly proportional to how bad the situation is and how much their capacities have improved over the years.
With that said, I'm not holding my breath on seeing major changes. I want it to happen but I don't exactly expect it to happen.