I hear a lot of complaining, but not really any compelling arguments.
"Creation Engine has huge physics problems when running at above 60 FPS, and is playing catch-up with modern game engines in virtually every area that counts."
We already know that statement is completely false, since Skyrim VR currently NEEDS (and does) run at a much higher FPS. Also, this statement is mostly copy/pasted from Forbes, which is not a site most serious gamers would rely on for an educated (gaming) opinion.
I think it's important to point out (again) that just because it's the "Creation Engine", doesn't mean it's going to be the exact same code base, and renderer, and lighting, and physics engine, or what have you, that Morrowind had. Just like the RedEngine will be on it's 4th iteration for Cyberpunk 2077, the Creation Engine is basically on it's next iteration of the Gamebryo engine.
So technically, no it's not a new game engine (Even completely new ones started from scratch will still use some form of similar code base. After all, axis and vectors are requirements for living in the third dimension). But for the average layman gamer, it will be new.
If the complainers here are saying that a new engine needs to be designed from scratch, give a compelling reason. I'm sure there will be theories why, but probably none of them will be based in any good facts or data. Most people here, even the ones with extensive programming experience, have little experience with a modern 3D game engine. This isn't some ray casting engine from the 90s that takes a few hours to code. You think you have problems now with the engine? Creating a brand new one from naught, is just going to give you a whole new set of them.