User blog comment:Care Level/RE: PBE Riven Nerf/@comment-3232747-20131219045644/@comment-9593635-20131219115424

Total AD isn't necessarily better than bonus AD, especially with ratios that low. If it were 0.7 total AD, it would be a buff, but it's not: it's 0.4 - 0.6.

Sunfire is buffed late game, but no ones roaming from top lane at level 15: laning is over, by then. All of the damage lost until that point is lost roaming ability.

CDR is still a good stat; this change just makes it impossible to realistically cap CDR on most top picks. Black Cleaver and... Ionian Boots of Lucidity? Either way, this directly reduces the presence of more/less every top pick; they've basically had all of their cool downs extended. Every top. Increasing the price would have been a better route, I think.

The nerf to the shield makes Riven take more damage at almost every stage of the game. It also makes investing any points in E (after the first) before the end of laning inefficient (you're essentially not even getting more shield for it in trades).

The difference in skill order is really what hurts Riven's potential the most, I think.