Stormtroopers are badass, man. Te opening battle in ANH aboard the Tantive IV is testament to that, as well as Obi Wan's remarks about them being so precise.
Obviously when they are fighting Han, Luke and Leia, they are gonna look like shit.
You put 100 Stormtroopers against 100 Clones, sure, the Clones would win, but it wouldn't be a curbstomp.