Thanks for your comments PPrune Towers but I must say that I am very surprised by some of them. You are right in saying that us "first world" controllers are fortunate to have good training and equipment.
I have never had a pilot complain I have been under separating them.
Whenever I have offered a RVSM level, I have never had any of them refuse it. This is what surprises me about your statement. If you are not happy with RVSM then tell someone. But I suppose you don't really have much control over it as its the bean counters who really want RVSM.
A couple of hundred metres in an offest is not really a problem. It would be very difficult to detect on a radar screen. But when off radar coverage the same problems as listed above will still apply. I am perfectly happy for you to do it as long as I am allowed to consider you "on track" for calculations.