AD scales so good compared to AP
If teams can go all AD as in zed or talon mid and have no ap on the team (support doesn't go ap either or pretend they don't in this situation). The all ad team is not penalized because ad usually ISN'T a skillshot that can miss in a teamfight. Only the tanky top and maybe support can build armor in the first place. The mid and adc DON'T go defense so they're still gonna get chunked anyway whether there's ad or ap. Nerf AD :D
Edit to everyone who responded: Then why do AD get the benefit of being viable while AP teams aren't seen? Cooldowns? Mana? Skillshot? Falling off?
This unviable support becomes GOD tier imo against a full AD team and you can also get items like
to mitigate their damage output. An all AD team has it easier then an all AP team because AD champions usually have the ability to deal DPS because of AA, but AP teams will be able to win too if they can blow up their targets. An all AP team is a lot more easily countered because their damage revolves around burst and if their spell rotations don't kill the target(s), they have a window while their skills are on CD to get wiped out.