I am glad as **** that they are using a new engine. You say that as if it were a bad thing. Even the engine for Oblivion used elements of the one used in Morrowind, so we are dealing with very old technology here. It is good to see Beth being progressive.
Im thinking the new engine was the result of sudden, unexpected and jaw dropping financial success. Bethesda is clearly moving in an obvious path: Release Game with new engine, license the improved version to other companies to make other games, profit. By fully developing their own in-house engine, this would take out a HUGE middleman in the form of Gamebryo. Not only that, its an engine that could very well be built from the ground up to handle some of oblivions complaints, where the old one sufferd restrictions: Open Towns, Levitation, summoning, or maybe changes on a vast scale that we cant even imagine yet. Imagine a system where Passwall could be an underpowerd joke--it likely wont be that extensive, but they can bring back a ton of the stuff they had to set aside in Morrowind and Oblivion.