This probably belongs in cross-game. Wouldn't have gotten subdefaulted then.
I bought it too and personally I think that what they did is perfect. They had a winning formula with Fallout 3 and Oblivion, and there was no real need to overhaul how the games *play*. It gets old when every time a company pulls out a new game you have to re-learn all over again how to move your character and shoot a gun.
That said, they made enough *subtle* changes that I can forgive them for reusing the engine. It's definitely updated - VATS is greatly improved. No more wild shots and a 60% chance of hitting an enemy actually means you have a good chance of hitting it. Those of us who liked Alchemy in Oblivion and missed it in Fallout 3 can rejoice - They have brought it back in another form.
Overall they did some really good things with the game and it's unfair to act like it has no merit just because they didn't see the need to write a whole new engine.
I mean, look how that worked out for SE. If it ain't broke, don't fix it.