We've all been round in circles about 123 combos, and most people agree, we don't want them as a healer. It just doesn't fit the role for various reasons, but it's not the only way to add more interactivity to the DPS rotation we have as a healer. More DOTs, GCDs with seperate recasts (like Sonic Break on GNB is once per min), procs off of other stuff we already have, etc. And we can add things to the buttons to make them more interesting. What about if Broil gives 2 Fairy Gauge, and Fey Blessing scaled in potency with more gauge? What if Dia ticks made the Lily Gauge tick one second faster? We can't just say 'well we cant do it because 123 sucks' and use that to write off every alternative.
It also falls apart when you ask 'ok so why do tanks have 123 combos', I'm not advocating for the tanks to get dragged down to where us healers are, but surely they don't actually 'need' a 123, it's just 'extra work for little output' right? Well, no, because there's more reason to have a 123 as tank. PLD and WAR have a branching choice of 'which 3' to use. DRK has it's lifesteal and gauge build attached to the 3rd hit, having it replaced by 111 would flood it in resources (or be retuned to feel really bad with how little each hit grants), and GNB gains a cartridge from it's 3rd hit. How would we make GNB get 'one third' of a cartridge to keep it's gain the same, 33% chance? That would feel terrible, not being able to guarantee having the cartridge to start the Gnashing combo because RNG didn't like you.
'Complex DPS rotation' does not mean 'good', but I'm not asking for 'complex', I'm asking for 'cohesive, fun, interactive'. One DOT that lasts 30s and a second button to spam until that DOT falls off does not a rotation make. As an aside, I'm playing 'the other game' and monks there do have a 123 of sorts. Difference is, there's all these different nuances to it that make that 123 play really well. 1 makes 2 strike multiple times. 2 has a chance per strike to reset 3's 10sec CD instantly. 3 applies one of their HOTs for 6sec instead of its usual 20s, but this HOT always jumps to someone who needs it, so its super unlikely to overheal. A CD that summons a bird friend, who will heal someone nearby whenever you press 2, 3 or 'Holy equivalent AOE spell'. When bird-friend does a heal, he gives a stack, and at 3 tacks, you can instantcast a second, 'usually 2sec casttime', HOT that also increases healing received by that target by 30%. An optional talent that makes 3 also extend your HOTs by 4sec duration, an effect so strong that it had to be capped to 'you can only get to double the HOT's original duration' because people got so fast at one point, they could keep the HOT up 100% of the time and just coat the whole raid in HOTs that never fell off. Should I go on, with examples of this 'actually an interesting 123 combo as a healer'?