Ziggs teaches us what the defining factor is for something to work in the botlane.

Purely in theory, a lot of mages would work really well with a support - they all have enough waveclear, DPS, carry-potential and can make enough use of the supports peel but unlike Ziggs, they don't get played in the botlane. I think the biggest factor that single-handedly makes Ziggs able to replace an ADC is TOWER DAMAGE.

The reason why every team must have an AD carry is to be able to finish and damage towers in sieging situations, they are the key to opening up the way to the enemy base and Nexus. Because they are the only champions who are ranged AND have strong tower damage there is no way around having one.

But then there's Ziggs. His W execute combined with Lichbane and his passive makes him demolish towers.

Until he appeared I thought that ADCs would never be able to be replaced unless something obviously broken like Morderkaiser is introduced but the solution is rather simple - we need to have more ranged carries besides marksmen that are able to take down towers like Ziggs.

There are some AP champions who could reveive changes to get this kind of ability in return for a power shift away from something else that they have, for example Azir with his W casts on towers or maybe making Viktor able to proc his Q attack on towers. Or maybe Urgot could get something too when he is reworked to make him able to take down towers aswell. The possibilities are endless.