I see myself as a very proficient shot, and very capable at placing bullets within 1" out to 300m's, albeit, not 'every' shot would fall within 1"!!
However!!! I would NEVER take a headshot, unless it was out of pure necessity - ie, to administer the last rites on a mis-hit deer, or if the deer was going to shoot me first
Like some others say, there's just not enough margin for error, and even though a heart/lung shot can go wrong, there's a pretty much guaranteed 4" killing radius, whereas on a Roe, with a headshot, the margin is surely no more than 1" before things start to go horrifically wrong.
I feel the same way about neck shots, the vertebrae is just too small to guarantee you will make a proper shot that will put the beast down dead, quickly..this is similarly noted on the deer commissions guides as far as I recall.
So unless we've started shooting to save our lives - ie. to put enough food on the table to feed our starving families, or to protect ourselves from deer with opposable thumbs and access to weapons, I don't see why one can't wait for a shot that is 'close enough to be ethical', and in a broadside position to 'place a shot that is ethical' - in that I mean, margin for error is highest, and thus likelyhood of unnecessary suffering is lowest.
IMHO - incoming!