User blog comment:Care Level/RE: PBE Riven Nerf/@comment-6000413-20131219095929/@comment-9593635-20131219223453

Renekton has a relatively bursty trade, but his all-in is just pure, sustained damage. And, given that he can now out-trade you, he has no incentive to disengage; he can just sit on you and outdamage you.

Olaf's true damage has no windup, so shielding it really came down to proper anticipation. And, again, his all-in is not bursty at all; since he now outdamages you (he did comparable damage, before), he has no incentive to disengage.