I think it's more realistic. Sure I have to thumb down to the d-pad to change my weapon but what soldier on the planet can instantly pull out his pistol without dropping his rifle? None I know of.
You probably don't know a lot of them then. No soldier is trained to ever drop their rifle and a marine would probably look at you as though you just insulted his/her mother for suggesting it.
Soldiers ARE trained however to maintain their off-hand grip and draw/fire their pistol with their main hand, unless the rifle is slung. I've done it with an AR-15 and a G-22.
Anyone with the correct muscle memory can perform this action in nearly a blink. True, not instantaneous, but pretty damn fast.
It's funny that you should mention thumbstick sensitivity, since most FPS pc shooters have similar preference settings. I COULD jack them up high enough to spin me around three times with just a twitch of the mouse, but that'd be rather silly.
Nothing is idiot proof. Nature WILL build a better idiot.
Consoles are pricey when they first come out and generally drop in price as time goes on. The technology is improved upon and made more efficiently, making the parts cheaper but the technology is typically the same for the life of the console. A PC can be upgraded to the latest tech for about the same price as a console fresh from the development line, or you could spend a little more and get hardware that will last longer than 2 years, or wait a little while and buy the same parts for cheaper.