TarheelsRule:
Actually Leon in real golf, the last 20 scores are used to calculate your handicap, the 10 lowest of those are selected. That being said you can significantly lower or increase your handicap index by just a few high scores if the oldest scores happen to be low and are going off the calculation. In wgt the method and large number of scores makes it take longer to significantly lower your score or increase it.
I know how the USGA handicap system works. Let me put it this way: A handicap can ALWAYS go up; in WGT, once you've played a certain number of rounds, your score average can NEVER go up.
If WGT used such a system, you could remain at one tier forever and still shoot great scores. Once you neared the next tier, you could play poorly for a while to raise your handicap -- over and over and over. You could shoot thirty 29's, then thirty 50's, then thirty 29's, etc, etc. The way it is now, you can only shoot thirty 29's once, then you get moved up.
With a handicap, those 29's will be eliminated from the pool of scores used to calculate your index; in WGT they never are. Sandbaggers are stuck with them. That's why they have to avoid ranked rounds. Use a handicap and they could win tons of tier ready gos, "disappear" for a while to jack up their index, then come back and shoot lights out again, winning dozens or hundreds of tournaments at tier X and never moving up.
That said, I agree totally with the idea of a WGT handicap, which would be great for cc tourneys, among other things -- but not for tier placement.