ADC Itemization
Mages, tanks, assassins and bruisers all have equal oppurtunity to itemize based on the enemy team, and their own needs.
When you come down to it, marksmen are left in the dust. Recently, mages got an itemization change which made them much healthier, and gave them much more options for build paths. Marksmen desperately need this.
How to fix this:
Split IE into two items. Very similar to how Zhonyas and Deathcap were split into two items four years ago, make it so one item has about 50 AD and the crit passive, and make it so another has the crit chance (say, 25%) and 40 AD. This will make it so crit carries don't powerspike with one item, but still have strengths and disadvantages if you buy one over the other. I think this will help a lot, even with one change.
Make other ADC items more viable. Essence Reaver is in an extremely weak spot right now. Although it makes it so you don't have to buy Manamune on certain ADC's, Manamune still ends up being better when it turns into Muramana. Muramana provides everything that Essence Reaver does, with extra damage. Essence Reaver only has that little bit of extra CDR and lifesteal, and has the exact same build as Bloodthirster. Essence Reaver either needs 20% CDR, 20% lifesteal, or a better passive. That's all I can think of.
This isn't necessarily for ADC's, but add different versions of Zeke's Harbinger. In the active of Zeke's, it states - UNIQUE – CONDUIT: Bind to target ally. This will remove all other Conduits on your target (60 seconds cooldown). So I guess I should say, add other "conduit" items. All of them would function similarly to Zeke's, but have different effects. One of them could have like 40% lifesteal, one of them could give them armor penetration, etc. I think this will not only change what conduit supports buy, but it could change what an ADC buys, if they no longer need the lifesteal, penetration, etc.
EDIT: This is a discussion thread. My ideas may not be great, but that doesn't make yours better. Unless they genuinely are. In that case, good for you.
Ideas suggested by you guys: None Yet!