adc players will tell you that adc are part of the meta and that it doesn't need any changes, while it does need changes because everytime a class was picked in every game (hello assassin meta) riot did massive item changes/balance changes to stop it. adc meta is here since season 1 and riot didn't do anything because xypherous mains adc.
futher more, adc players will lie to your face telling you that it's impossible to not make adc picked in all games because you need them to take towers, and again this is not true.
you have a 0.8 ap ratio damage on towers, which means that if mages have 800 ap, they will deal more than 600 damage to towers on each attacks, and that without counting lichbane or
.
basically to siege, you just need a ranged character in your team jungle/top/mid, but you will always need an adc because they have the best early game combined with a support making an melee unable to lane bot.