Looks good, not if we can only change that matte.
As for clouds moving, that's not always necessary in a 5 second or so shot. In real life sometimes the clouds move so slowly you can't hardly notice any movement at all in 5 seconds. Yes, at times clouds do move rather fast, but almost as often if you line up the edge a cloud with the edge of a telephone pole or building you get not discernable movement in a 5 sec period.