Skilled healers can heal without using gcds while spamming dps and this gets spammed all over as THE way to play healer. Unskilled healers see this and spam their dps skills without realizing they need to at least be using ogcd heals appropriately leading to lots of unneeded deaths. SE attempts to rectify the issue by making dps easier to do by simplifying it and having more ogcds. Literally the exact same thing happened to tanks from HW to SB with the whole dropping tank stance thing. You ended up having a lot of new or bad tanks losing agro nonstop until SE steps in and kills aggro management. Really, if you think about any of the weird or annoying class decisions they've made since HW, almost all of them stem from people screeching about optimization.