Geesh, somebody's got to come up with some negatives around here! :s
Seriously, the Road King is a great bike and it was a very close second choice when I bought my Street Glide a year ago. For me, the main down sides to the RK were no fairing, no stereo, and fewer gauges. Very minor point was that I didn't like looking down at the speedometer - as a pilot I like my gauges in my peripheral vision where I don't have to move my head so much. Huge positive for the RK, and the reason I almost got one, is the ability to pop off the shield for short rides around town - I love the look of a RK with no shield and that huge headlight!
Like everyone else said, if you get a 2009 or a used bike with a stabilizer already installed, the wobble is a non issue. Or if you're like me and mainly ride a relaxed, cruiser style, it's a non issue anyway.