Indeed.

But barring store changes to adjust the need for duo lanes to split gold, most of the stuff here is the framework that even pros need to build their metas around.

The logic for lanes seems good...

but why do you need a ranged ADC?

Why DO you need an adc?

ADC is a role that specilizes in the "protect the kog" type strats, where you have a powerful offence (damage/crit/attack speed/%pen) tied to a glaring weakness (dies if sneezed on)

While this is a powerful strat, it will often fall apart in solo que, if your team doesnt peel off your attackers well enough. Personally, I love taking Ryze (a magic damage DPS, who builds naturally tanky) bottom, with an ad assasin mid

you technically don;t need a ranged adc. however these are the reasons you should have one.

1) they have the highest sustained dps
a) they accomplish this because they have built in steroids. take tristana for example. her q gives her +90% attack speed.

2) they are ranged so can attack from a distance instead of being in the middle of everything getting hit by all kinds of aoe. for example GP is a melee carry but if he builds glass cannon he will get instantly owned because he has to be wheere all teh action takes place.
a) because they focus on damage all adc's will build glass cannon with at max 1 defensive item (GA for example). this means they need to be away from the action.

3) its about balance. by having multiple champion types (tank, support, assassin, ap nuker, initiator, adc) you become a more balanced team.
a) if they build to defend against you, then your ap will wreck them and vice versa.