I was also missing the 3-finger swipe in safari and finder, but also thing think the two finger swipe is good also, especially for pdfs. If you change the 'Swipe between pages' to 2 or 3, it gives you the old three finger back, but doesn't lose the new two-finger gesture. It does mean the swiping between full-screen apps moves to 4 fingers, but that is manageable. Much happier now I've found that.