Why does there have to be an ADC? Can we add some diversity?

    Why is there have to an ADC? Because Rito made ADC a default mechanism of game after the CLG.EU strategy. So **picking an ADC makes the game easier. You take the towers easier, kill the tanks easier and win easier.**

    To be detailed, ADCs always don't have nuke, no high-scale spells so they don't go attack + armor penetration items. The only option for ADCs is always AS+Crit. Those items always expensive and not defensive, so they need 3 items and a long farming time to get a decent damage. ADCs are good for killing tanks than everyone else, for they have the strongest items in the game. ADCs are always squishy in base stats and lacking CC/escaping spells so they need support to protect. an ADC must get most of the gold to be useful, so there have to be with a support who needs the least gold to be useful.

    In the meantime, Rito decides some champions have to be support and sacrifice for the team. Yes, not just the players need to sacrifice, champions have to sacrifice too! Hence, supports' AP/AD scales have been reduced hugely. It's way harder for supports to do damage. You probably always think of running when meeting enemy a carry in the jungle if no teammate is behind you. Unless you are way more skillful than the enemy, like hitting every Thresh Q, E and kill the enemy with sunfire cape. (Okay, as an exception, I don't know why Tahm has percentage damage). 

   The only way supports (regular support champions instead of Zyra, Brand and Annie) to carry the game (in your own elo) is to play around carries, like giving kills after a good gank, saving lives and a good engage. Supports have the least gold efficiency in the aspect of damage. Also, supports are less tankier than any tanks and have less damage than tanks. Supports' damage scales were all transferred to a bunches of functional spells like speeding up. Regularly, you just have tons of CC or low-AP-scale heal/shield and you must fight under towers. Yes, towers, not your own damage.

    At last, Rito doesn't want to increase AP's ability of taking towers. Also, a death cap doesn't grant you the ability to eliminate tanks. 

** It's actually easy to add diversity. ** 1. Buff ADC's spell nuke and nerf DPS. Refuse the existence of perfect combination like high AD+Crit+AS on ADCs, or just delete critical damage. Cut the price of the 3600 and 3800 super items. Give ADCs more early game and mid game item options. Make them gank/farm instead of only farming or fighting with support's help. 2. Increase APs' ability of taking towers.

    In this way, ADCs are not the perfectly solid DPS in the game.  Other options would also work, but ADCs are still the most solid. But you might want to be more aggressive, so you pick TF because he's a solid ganker. You might want to be extremely safe, so you pick Xerath. You might want to get a multi-tank team, so you get a Vladimir bot. They are all possible picks.

    Then give supports damage back. II mean supports still should farm the least gold. They still should control most of the vision and maybe sacrifice them for saving or engaging. But they also need to be able to carry the game with highly skilled outplaying, by killing, instead of protecting. Supports still sacrifice themselves because carries are still better in late game. But If carries are not carrying the game, supports are not supposed to lose because of bad teammates. They should have damage to make a comeback. Moreover, when supports potentially could be a carry, there don't have to be the most solid DPS, ADCs, in the botlane.

    But Rito won't do this.
    ADC has been a core mechanism since S1. Changing the whole botlane might cause highly unpredictable results. Not only in the aspect of game balance, but also about players' response including professional players.

Some time ago, they nerfed Youmuu + Black Cleaver Lucian. Then Youmuu + Duskblade ADCs. Now you have functional ADCs like Jhin and Ashe, ADCs are not considered only late game carries but more engager. It's a good sign of bringing other champions to botlane. Then Rito wants to remake Youmuu. Because ADCs are not supposed to fight in mid game. Rito designed a botlane Mordekasier. They gave him a dragon. It's obviously an unique mechanism. Even if it's successful, you can't add it on other champions. So it's not even adding diversity. And now they leave Mordekasier alone in the corner. Awesome. I used to play mid Mordekaiser (and AP Tristana, not in ranked) a lot, just to let you know.

It all depends on how you designers think. But how do you think? I have no idea. But at least, I wish you will consider testing this on PBE.