RedEngine 3 is an iteration on the engine CDPR has been using and improving since The Witcher 1, and not to dismiss the tremendous work they put in toward achieving their open world, but the game doesn't look or play all that different from Witcher 2 outside of the open world mechanics and some combat rejiggering, so I'm not sure why you posit that as a huge game changing engine revision. And the other 3 engines you mentioned are game engines designed foremost for licensing or intercompany development, engines that particularly hinge on their ability to produce competitive and industry leading visuals.
I think that as long as this game runs considerably better and more consistently than previous iterations while looking the way it does (considering the things I mentioned in the above post), it will represent a reasonable advancement for the engine.