@RIOT kha`zix weird scalling

hello ,just wanted to know why passive scales from ap ,which is almost never bought ,except trinity /baron buff ,but ekko etc...have normal scaling ,with their main stats for example how would it be that you build ap ekko but passive scales from bonus ad? ...weird enough?

ideas: why doesnt khazix get some total ad or bonus ad scaling on passive ,or passive works on jjungler creeps so that he can clear a bit faster and lose less health in jungle (squishy bug)

then the heal is 80 -160 + ap ,again ..why ap ,what if riven shield scaled from ap ?weird heal can be reduced ,spamable shield cant so ,why doesnt W heal scale from ad ,or better.... like rengar`s? the lower khazix is on health the more hp returned ?

W cooldown is really big and lower damage ,both nerfed ?no revert or give something back ?

E has lowest bonus ad in game? 20% ? would it be good to increase it to 50-60% ? was 80% bonus ad

then about R ...was 40% damage reduction while invisible ...then it went to 50% ,then it didnt reduce damage from turrets ,because tower dive unhealthy ?but now is 0 % ?

would you consider making it 15-25% reduction ,isnt much but helps not die like a fly

thanks