It's not fun uploading 2000+ 21MP RAW images to your desktop or laptop then backing all that up. Can't imagine doing that with 36MP images. And then there's the processing time, I would need a lot more processing power to cope.
I do this frequently and have no problem with it. Doesn't take so long.
Having a camera that fulfils your needs is only part of the job, having the processing power to match is equally as important - some would say a prerequisite.
I would love 36MP Raw files if the camera can also do 12 fps like the 1D X, or even faster. Don't mind at all.