How much of the marksman rework is going to be in items?

One of the biggest things about ADCs is they all tend to use the same build, with one or two options between champs. How much effort should riot spend trying to give us a little more variation in ADC builds? Unless your ADC really needs AS or is a caster, you start IE. You can't play ADC without getting one of SS, PD, or TF. BT and Bork are pretty ubiquitous. LW is a must, as is BC in a tank meta.

Hurricane is pretty much ignored. ER is ignored even though it enables your offense all around. Manamune is only good on Ez and Urgot. IMO a ER rework with an earlier mana item might push manamune out. BC is more of a niche thing. Hydra has good stats and is an easy build item, but the passive is useless on purpose (I wonder why with SS and hurricane in the game and it works in SOADA on ranged champs). Maw is generally only built on melee champs. Mirage blade is gone. Youmuu's is niche.

What could/should happen with ADC items?