Some of Oblivion was oversimplified...and for a fair enough reason too. It was Bethesda's chance at hooking a broader market on the elderscorlls series. Oblivion was supposed to be a next generation launch title. In order to sell the game and more importantly the console, it had to reach a broader spectrum of customers.
Now that it has done so thanks to the help of Oblivion, i'm sure Bethesda will build a much more sophisticated game with an enriched plot.
Look at Fallout 3 compared to New Vegas. People (like myself) had never played a fallout game previous to Fallout 3, so I had to learn all the games factions, and what exactly was going on. When Obsidian released Fallout New Vegas it was much more complex than Fallout 3 in terms of the storyline and the rivaling factions. If it was done the other way around, I can see how it would put off casual players.