Just a thought:
(Inspired by SD's infinity edge stacking Jayce concept)
With all the nerfs in attack speed and overall buff in ad items (and also subsequently the decrease in AD carries' strength), something stood out in all this chaos and that's Jayce's ranged W, which at max rank gives him MAX attack speed and extra 30% damage for 3 autos, on a 6 (min 3.6) sec cooldown. In other words, Jayce can just build AD and cdr, instead of AD and atkspeed, and have a dps that probably outdoes every carry except maybe Vayne. Oh and it's also an autoattack reset too. Plus, since you're building cdr instead of AS, you can spam your other abilities too (and Jayce has lots of utility behind them).
The build would be something like Ionian Boots/Cleaver/BT/Ghostblade/Warmogs/Infinity Edge, which gives you 39% cdr (if you include the cdr mastery @offense), 30 base arpen (on its own), and 40% crit (5% more than triforce ez, though no one really builds that anymore i think). Activating W gives you approximately +110 AD for 3 attacks and the bonus can also crit. Despite his 500 range (which, is shared by Sivir and she does fine. If necessary Jayce can transform and QW auto E for a quick disengage and re-transform), could we perhaps see more carry styled Jayce in the future?