Why the extreme of 'just one potency difference'? As with many things, there's a balance to be struck with this kind of stuff. As I said before:
So your hypothetical 'I dont like complexity or DPS rotations' healer could choose to ignore the DOTs entirely and use Broil (295p) in their place. This would be, per 2min (lowest common denominator), 4 Biolysis refreshes, for a total of 420p, 5 Miasma refreshes, for 325p, and 8 Shadowflares (assuming they're not on a CD like in HW or SB), for 600p. All in all, the total potency they lose over two whole minutes in this situation, would be 1345p, roughly four and a half Broils. But for players who like to have more than just one button, three whole DOTs to manage timers of. Please stop with the 'take it to absurd extremes for sake of trying to make idea look silly' because it's not going to work. If Hypothetical Healer is doing EX roulette and doesn't want to use DOTs, nobody's going to chew them out. Heck I could go through EX roulette now if I wanted and just not use my DOT, nobody would even notice. The idea that they would 'have to' use the extra skills is, in casual content, flat out wrong, and in higher end content, potentially wrong (depends on enrage timers).
But even then, if someone is in a fight where that kind of 'perfect DOT juggling optimization skill' is required (so, week 1 or 2, final fight of tier on savage), they're competent enough to also be able to actually spin the plates. There's no healer that's simultaneously good enough to do such high end content where that level of skill is necessary, and at the same time, is too incompetent to actually interface with a more complex kit like I/others ask for. It'd be a paradox, or a very painfully obvious clear-buyer.
Good thing you brought up Druids though, cos I'm playing one atm in DF. You mention Wrath spam as the way to do damage, but I'm sure you weren't planning on forgetting about how you can also cat-weave, putting up Moonfire, Sunfire, and both Rip and Rake from Catform? Or how in Shadowlands due to Convoke the Spirits, Resto Druids started taking up the concept of Owlweaving (or Boomboxing as some called it for some reason), since Convoke had a chance to throw out the very powerful Full Moon? So yeh, exactly what I'm, and others, are asking for ironically: Casual healers can just heal/spam Wrath, healers starting to get into the groove of knowing when to damage can start juggling the 2 DOTs from caster form, and epic hardcore M+25 running gamers can start juggling 4 different DOTs with staggered timers, from two different forms (which are on the GCD). As much complexity as the player wants to dive into, or not. Some people want to stay in the shallow end of the proverbial swimming pool? That's fine. But I'm 2m tall, I got long legs, and the shallow end is too shallow for me, I need some... depth. I wouldn't want to drag everyone else into my deep end where they'll drown, but I'm also asking that they don't fill in the deep end so I can't swim. And that's where we are now, all four healers are 0.6m deep and I keep bashing my legs on the bottom of the pool, because of the lack of depth. And I'm pretty sure I'm not the only tall person in the world, just like I'm not the only healer main who's disappointed, helplessly watching as the depth of the role gets filled in more and more, levelling out the whole proverbial pool until it's all just as deep as a puddle