What's with base AP?

not realy, most skills scale of bonus-ad, not total, and those with total scaling have a low scaling and low base dmg on lower ranks

Giving AP champions a large amount of AP innately would be pretty broken. Could you imagine a Lb starting off with 50 AP. Another 30 from Runes/Masts and it's essentially the same as her walking around level one with a needlessly large rod. If champions were to have innate AP, it would have to be a small amount to avoid giving excessive amounts of early burst.