If you look at the new change to all long-term CC, where the abilities no longer aggro mobs by themselves, Blizzard included Blind in the list. However, they included *no* short-term stuns/pseudo-CC. Further cements that Blizzard just reclassified Blind into a long-term CC ability.

This change might be better understood, then, as giving rogues a second PvE CC ability, rather than as a PvP vs. PvE issue. There are other classes that can CC two mobs at a time (hex/bind elemental for shammies, banish/seduce/fear for warlocks, hibernate/root for druids, trap/tranq for hunters), so they're just giving rogues some CC love.

I realized why Blizz needed to give rogues a second CC, because Sap can't be reapplied in Combat, while Blind can. Although, a 3 minute CD and a 1 minute duration doesn't help too much, but I guess that just means we need to kill our other targets faster before the sapped/blinded target wakes up.

Yeah, this change just gives us a way to be able to actually keep up some CC during combat. You can't reapply sap, but you can blind the target when it comes out of sap if you need to. And with the 3 min cooldown, it can't be reapplied every time. It just stretches a rogue's CC time out a bit, since you have some classes like mages who can CC basically indefinitely by reapplying polymorph and the like, but rogues only had that one-shot CC.