Again you try to bring this to "well only for high-level content" when you've been posting everywhere about "muh playstyle". Do you change your playstyle between faceroll DR content and EX/savage content? No, I don't raid anymore stalker. Yes, I did raid - I ran and cleared coil long before HW came out and my healers (especially SCH) DPSed. I gave up raiding after A2S partly because of the high DPS checks required and getting burned out.
Raids and primals are pretty easy to DPS in as a healer (and tank) since you know EXACTLY WHEN you need to heal and EXACTLY WHEN you need to shield and EXACTLY HOW LONG you can stay in cleric stance DPSing before switching to heal/shield. These fights are 100% scripted, so you know EVERYTHING that will happen and should be coming in with a plan for what you're going to do and when. The ONLY time you have the excuse of not knowing what to do and doing reactionary healing is when you're trying to run world first clears and it's the first time you saw XYZ mechanic or you've pushed a phase that you normally don't push. Same with tanks and DPS. Once the fight has been cleared, there are videos (even full length clear videos from multiple perspectives) that you can watch so you know the timing. So if you're mashing your cleric button trying to panic heal all the time, either the groups you have are REALLY bad and taking WAY too much damage or you didn't come in with a plan.
Content that is unpredictable is DF because you have no idea if your tank is going to mitigate damage correctly from the 12 mobs they pulled, how many mobs the tank will pull and if DPS will stand in everything. Still healing requirements being as low as they are you should be able to comfortably DPS through most pulls.
If you find the requirements for savage tier raids and ex primals too daunting and feel that your skill level is too low; either work on improving yourself or chose a different class. Don't ask that the content or class be changed because you specifically can't handle it. You want to be in the top 30%, then improve yourself - don't ask for the content to be made easier.