I'm pretty sure they're going to do it eventually. Contrary to what some people believe, there is a lot of incentive for CDPR to do this:
1) The Witcher 3 is an immensely popular game that will be played by many gamers for a very long time; especially on PC. Games can remain viable for many years after launching on the PC platform. CDPR knows this, so it's in their financial interest to give the Witcher 3 the longest legs they can. Especially since they earn an enormous profit from it on GoG.
2) It's a matter of pride. They will never fully escape the downgrade controversy that tainted the Witcher 3's launch until they redo the entire game's assets with the updated engine capabilities.
There's also the question of performance. The base game suffered massive performance issues on the consoles for months after launch. The new engine updates helped to improve performance dramatically for B&W on the consoles, so these should definitely be rolled into the main game if they want to cultivate themselves as a true AAA multi platform developer.
You are absolutely right, an
Enhanced Edition would make a lot of sense from a financial perspective as well.
For me though, not having a definitive edition of
The Witcher 3: Wild Hunt would simply be doing a great game such as this one a major disservice by leaving in bugs and performance issues. I want this - my favourite game
ever thus far - to be an experience that I can revisit at a later date, on more powerful hardware, and not have to worry about technical glitches, LOD and pop-in issues, etc.
Geralt's saga is just too damn engrossing to have to put up with such problems!