I know everyone wants an anniversary badge before they hit 4 years (OK - I wouldn't mind one, either!), but here's my take on the Anniversary Badges:
Think forward about 4 years - at that point in time, every one of the 80,000+ current members (that are still active) will have a badge. If you think that maybe 50,000 of us will still be active and get badges, and that the membership level could very well be at 200,000, that means that 25% of the membership will have 4-yr anniversary badges.
I'm envisioning that by that point in time, we will have not only 4-yr badges, but probably 6-yr and 8-yr. My prediction is that the time requirement for anniversary badges will go up, not down.