It has been my experience that FG correlates only loosly with mouthfeel. There have been many highly attenuated beers with a full mouthfell and poorly attenuated ones with thin mouthfeel. I expect that yeast plays a big role as well. The residual sweetness also depends more on residual fermentable sugars than on the actual FG.
I agree and I think personal preference is a really big part of the equation. Some people can drink beer up to 1.020 and enjoy it. I recently tapped a barley wine that finished out at 1.014 and I think it's too sweet. In fact, anything above this level seems sweet to me. In the case of my barley wine, I should have upped the hops, but that's for another thread.
Most of my beer finishes in the 1.010 to 1.012 range, generally on the lower side, and I think it has good mouth feel when I compare it to similar commercial styles.