"I used to use those huge picks, called Big Stubbies.
I switched over to a light pick a while ago. As far as I can tell the benefits of a lighter pick are less picking noise, improved control, and easier rhythm playing.
The only benefit I've found in using thicker picks is a phatter tone when playing leads. But if you're playing anything fast or switching between chords and rhythm a lot, forget it, use a light pick."
I agree partially, but mostly not. I think you are lumping thick picks and big picks into one category. While the big stubby may be both thick and large, there are lots of small thick picks (Dunlop Jazz III, or Jim Dunlop "Stubby") that I think are optimal for playing fast melodies. You're right, however, in that larger, thinner picks are easier for strumming chords.
Playing with a thicker pick means that the pick has less give, and the string will give before the pick will. When you play with a thin pick, you have less control over the string because the pick can bend and compromise your attack. When I'm playing single note lines that require a lot of accuracy, and when I want the subtlety of the attack to come through, I always use thick picks.