reasonable balance change suggestion to Rivens E

• valor cooldown increased to 16/15/14/13/12 seconds from 10/9/8/7/6 seconds

• every time she procs her passive on a champion, the cooldown is reduced by 2 seconds, this can only occur a maximum of 3 times per valor cast

although numerically it seems like a straight nerf, due to the way percentage cdr works, the passive proc cooldown mechanic can potentially cause the ability to go on a much lower cooldown than it currently is on live with cdr items, which rivens tend to stack a lot of anyways (assuming valor is max rank, at just 20% cdr the cooldown is now 9.6 seconds versus 4.8 with live values with 3 passive procs causing the ability to go on a 3.6 second cd, with 40% cdr her passive would now have a 7.2 second cooldown versus the current 3.6 second cooldown, proccing her passive 3 times could potentially cause the ability to go down to a miniscule 1.2 seconds)

the idea behind it is risk/reward, riven is now rewarded for sticking onto her target and using valor offensively, but using it purely defensively or getting kited punishes her hard