"Yoshi P: Up until Patch 5.3 we heard from a lot of players that healers had a fair amount of downtime on their hands. So, from Patch 5.4, we’ve planned for the more difficult content to put out a lot more damage more often. For speed clears we are planning for it to be harder to do with just pure healers or just shield healers."

Seems like a case of 'hearing from a lot of players' but 'not actually understanding the issue'. Yes healers have a fair amount of downtime - in almost any kind of content, even more so in lower level and 'easy' content. Changing it for 'hardcore' content going forwards will not fix the issue, its a band-aid at most that ignores the main bulk of the game where it actually matters.