Although most of the AD items did get extra abilities, their raw stat efficiency has been sharply reduced.
Essence Reaver lost almost 20% of its AD and now costs 300G more.
Phantom Dancer lost 5% attack speed and crit chance, plus the passive movespeed in return for a 100G cost reduction.
BF Sword lost 20% of its AD but only 16% of its cost.
Bilgewater Cutlass costs 250G more for only 2% more lifesteal.
BotRK costs 200G more and does less damage with the passive.
Bloodthirster lost 5 AD and costs 200G more in return for opening up the 'BT stacking' build.
IE lost 20% of its AD and 80% of its price.
Last Whisper does now give more AP per gold, but not only is its passive 30% instead of 35%, it now only works on BONUS armor.
In all fairness, Dagger, Brawler's Gloves, Cloak of Agility, Stinger, Mercurial Scimitar, Runaan's Hurricane and Berserker's Greaves did actually get more efficient, mostly in small cost adjustments. However, most of these are component items, intended to ease buildpaths and buff lane-bully AD carries; most ADCs will still end the game with the lower-stat items above.