question

So an adc build attack speed and damage to perform his best... , and critical items , but his base attack damage from start is 65 damage or around that value + runes damage optional..

My question is how an adc can build only attack speed and benefit his attack damage power... , while someone as a mage have to start 0 ap , and have some basic attack damage which not even interact with abilitys or his kite... , aka veigar , syndra .... etc... , there are champions who use basic damage effect much more great than someone ap... , for exemple if adc get's feeded early he buys some damage and attack speed and he get's insane , if a guy who is mage plays mage, he have to first kill and farm to get ap items as he start almost from 0 ap ,and he gets ap just for items and runes... early .. So my question is ,why does the ap mages have to start with 0 ap ,why them basic ability power damage is 0 ??? , they depend really much about abilitys they hit , while the adc dosn't depend of such stuffs that much as they can just basic withour that many risks to miss something.. .

Does it makes sense?? or not ?? . I think the mages should start around 55 magic ability power and get denyed the basic attack damage to 0 , so they basic attack based on a percent of them ability power ,for exemple you have 100 ap builded ... ,then you deal 70% of your ability power as basic damage... , you have 200 ap then you deal 50% of your ap damage as basic etc... , i think the fact a mage use basic attack damage makes no sense ,as the mage should have ap basic attack damage.. , and it should scale according to help his kite and build ap to kill enemy with his abilitys.