Understood.
Speaking of time consuming things of this nature.. I've gone through a few songs that weren't recorded to clicks, and adjusted the grid/tempo at, at least every bar, so as to line it up and program midi along side them. For eg. Machine Head - Blood Of The Zodiac, that took forever.. mind you I was programming an exact drum track. haha then the peeps I did it for said it was too fast or slow in spots.. yet it played next to the fucking song. Admittedly it did sound somewhat weird because the tempo changes I was trying to copy where were very subtle and human, great drumming.
I've done this for some Meshuggah songs also. It's given me the opinion that if you have a good/gifted drummer, their feel should be trusted to guide the song.. or at least given a chance. The 2 songs that come to mind are Machine Head - BotZ.. the tempo 'swells' and 'contracts' (for some reason these words seem right). And Meshuggah - Sane, the lull in the song slows down quite a bit. Both songs are perfection to me, but technically they are not.