Cylons try to strike with superior numbers because they are "incapable of independent thought" which is a significant military weakness compared to independent free-thinking and highly adaptable humans.
It's like some sort of cybernetic blitzkreig, the trick is to have enough ships to overwhelm the humans because I can imagine the CF defeating a Cylon force that outnumbers them 3 or five to one.
Of course the odds are significantly reduced if you've fooled the enemy into thinking you're suing for peace.
