Riot's new item to play without marksmen will do nothing if ADCs are kept in their current state.
Let's say it is an starting item which gives melee carries the potential to lane against ranged ADCs, melee-only, with a shared XP passive, some AD and some sustain.
It won't change a thing, because ADCs are just that stupid right now. Crit is stupidly cheap and lets hypercarries do what mages and assassins do at midgame, without ever falling off because they're fucking hypercarries. Crit needs to be more expensive, especially the Zeal items. 2600g? Seriously? For a class designed to be at their strongest in the later stages in the game? Even fucking Duskblade (which is still fucking bullshit) is more expensive, for fuck's sake.