The term "dumbed down" isn't really accurate, but making a game primarily for consoles does come with some losses - most importantly, the number of buttons you can effectively use.
For example, Crysis 2, being a cross-platform game, has lost free leaning and lying prone, two things many PC gamers used to take for granted, but due to the fewer buttons on console controllers there's simply no room. The game hasn't been dumbed down, in that it's made for less intelligent people (Because a game where driving a jeep through a house, then blowing it up, was a viable combat strategy was never going to be built for intellectuals), rather it's made for less flexible control schemes.
@SURPLUS_NINJA: The clock speed of a processor alone doesn't tell you anything about it, as it says nothing about how many instructions a processor can complete in one cycle, or many other important statistics. Processors now are much more efficient than they were 6 years ago, where a 6 year old 3GHz processor will be blown out of the water by, say, a 1.4GHz i3. Processing power is insanely more powerful than it used to be.
Lack of buttons causing lack of functionality is a real serious issue I missed beeing able to take better cover in Fallout 3, why not a take cover button where your character finds the best cover at his position while still being able to see the target?
Anyway always hated only 8 shortcut buttons in Oblivion is a pain for a mage who use different spells on different enemies and tactical situations.
However Oblivion was not dumbed down from Morrowind with the exception of the quest compass. Yes many features like cast on use enchanted items, spears, throwing weapons and crossbows was removed but this was done to remove exploits and reduce the number of animations.
Oblivion is less forgiving for novice players than Morrowind as it get harder then you reach higher levels, no problem playing Morrowind at level 25 with a gimped character.
And yes good point about the clock speed, core2/ I series cpu's does almost twice as much as pentium 4 each clock cycle for each core.