Some incoherent questions...

For the drumming question:

I'm a drummer, and i can do the drumbeats pretty much perfectly well.. except i can't do double bass blasts - this is actually down to the fact i have a problem with my legs where i phsyically can't do it :( (which sucks seeing as i want to be a metal drummer). I guess that if you practiced for long enough you could eventually get it, but sadly for me i don't think it'll be possible.
 
As an opeth fan, you are accustomed to listening to songs that move from one riff to the next, without returning too often to a previous riff. Usually just once, later in the piece. With TGC, you just get the same riff over, and over... with occasional deviations.

It tests the patience of the average Opeth listener - in the opposite way to the way that Opeth tests the patience of the average music listener!

That is why I don't really like TGC as much.