I don't play Guitar Hero. That has nothing to do with whether the game is easy or difficult, or how good I would be at it (probably not very). But by just looking at the gameplay I can say that even if I was perfectly able to press all the buttons milliseconds after they flash up on the screen, I just wouldn't be very proud of that. Being able to press a button fast, without having to think *which* button to press, is not the sort of gameplay that satisfies me. I'd rather have some seconds to make an interesting choice which move to make, than having to make an obvious move as fast as possible.
For pretty much the same reasons I opted out of raiding in World of Warcraft. With every expansion raiding in WoW resembles Guitar Hero some more. The game, or some addon, tells you what button to press, and you press it as quickly and correctly as possible. That can be difficult, but the difficulty is all in the execution, and not in any hard thinking or decision making. If that is the gameplay you like, more power to you! But personally I'm not all that interested in Guitar Hero dungeons.
If you don't raid in World of Warcraft, you don't really need the rewards from heroics. That gives you pause enough to examine whether you actually like the gameplay of heroics, whether they would be any fun without the rewards. Unfortunately in Cataclysm the answer for me is "no". I am not having fun in heroics in Cataclysm, beyond getting a reward I don't really need. That stems from a combination of factors: Heroics in Cataclysms becoming more like "raid lite" with the same sort of Guitar Hero gameplay, the sheer length of them, and the bad behavior of other players. I even lost interest in running heroics with my guild after a guild mate chided me for wearing what he thought was a sub-optimal piece of gear, an event which showed again how few choices you get to make in WoW these days.
From quest instructions, to gear choices, to talent choices, to what buttons to press in a boss encounter, World of Warcraft has turned into a game where somebody else is always telling me what to do, and I am expected to mindlessly follow these instructions without thinking for myself. That is considered "hard" if either I'm just given a fraction of a second to follow that instruction, or following that instruction takes many hours. That is not the kind of difficulty that satisfies me when I overcome it. And if I make any choices on my own without looking up the optimal solution, I'm considered a moron. Where is the game in that?
My World of Warcraft subscription is running out in a month, and I decided not to renew it for the moment. I'm taking a break for summer, for single-player games, for SWTOR, for Guild Wars 2, for whatever, until World of Warcraft adds some content that again interests me.