I think it's an awesome engine that in my experience ran really smoothly even on a somewhat older system before I did an upgrade. I also had to do almost no fussing, tweaking and whatnot.
I agree. The engine seems quite capable and ran just fine on my PC. It just seemed that some of the more interactive concepts were totally underutilized.
Had this not been the case, the joy of exploration and discovery could have been greatly enhanced.
I keep having this feeling that developing the MMO aspects of the game caused the single player gameworld to be underdevloped and less interesting.