Well, to be honest, Clones aren't "dumb" but they aren't brilliant either. Taking orders doesn't mean intelligence, it means they were trained well. Plus, taking down Jedi doesn't show intelligence either, if you have numbers you can just overwhelm the jedi. Winning battles goes along with taking orders, they couldn't have won most of those battles without the help of their generals (mostly Jedi).
On a side note, Clone Troopers are more "street smart" in a sense. lol but by street I mean battle. They know what to do in a pinch but they probably wouldn't be able to have a discussion on Calculus.
Think of yourselves as a hand. Each of you is a finger, and without the others you're useless. Alone, a finger can't grasp, or control, or form a fist. You are nothing on your own, and everything together.