can anyone from the UK seriously imagine facing dptdexys with an extra 300 points to spend on his codex marines?
verily he would be as a hound with two sets of genitals....

But in all seriousness, I think that in the UK at least, we've attained a level where most lists are competetive against most other lists, and if a list is seen as weaker, either it gets some buffs, or people play it as a flavour list and either try something drastically new with it (looking at you Mintroll) or play for the fun and don't expect to be competetive
I think the 'tiers' are a highly subjective thing, for example when looking at the UK Ghazgkull list, it has a lower win percentage than others, but that is in part due to the fact that RichardL, Steve54 and dptdexys haven't taken it in a tournament and their prodigious playing skill hasn't skewed the list/stats. So if you were ordering the lists according to tournament data, the orks may initially be placed in a lower tier, which may mean they gain a disproportionate advantage for a while.... the other method is organising them in a highly subjective way which will inevitably never reach consensus and may lead to people sulking and not participating because they feel their list has been disadvantaged unfairly....
Great players win games, regardless of lists or anything else....