Blaze Magician the weakest koc???

I know there are supposed to be pros and cons for each class...but from the stuff I see in youtube (like the koc against the Black Magician) otherclasses almost always consistently do above 10k damage, whilst the Blaze Magician does only around 5-6k.

Is the rumor that BMs are strong at first in lower levels up to level 40 or so but then fall behind the others?