I don't disagree, but there are two historical things that pose an issue with that. Not that *I* have a problem with addressing those things, but we've seen them play out in how healer design has worked over the past 6ish years.
1) The "complicated" healers tend to...not be happy when the "simple" healer has equivalent output. Rabble rabble "we should have more output for being more complex" rabble rabble, which totally ignores the fact that, if designed this way, what you end up with isn't simple vs complex; you get novice intro class vs directly superior upgrades. I've seen this argument break out basically every time Babby's First WHM gets anywhere close to the damage output AST and SCH have. That's the rub though. If WHM has nothing going for it other than direct healing and damage, and it doesn't uniquely shine at either one of them, then it's just dead weight.
2) Historically, for WHM at least, "simple" hasn't just been a DPS complexity thing. It's lacked anything engaging to do outside spamming Stone and basic b*tch heals that don't really build to anything, maybe the occasional utility oGCD with a long cooldown, often from the role system. There's simple, and then there's simple. WHM's unbelievably simplistic design drags the entire role down when you factor in Squeenix's need to keep the jobs balanced. When your competition can regen, and do fantastic personal damage, and shield, and reduce incoming damage, and buff party damage, and buff party speed, and debuff the boss, and move really easily, and weave without difficulty, and their downside is that they can bring the entire party from empty to full with three twitches of their fingers instead of two, then the healer that can do only the first two things reliably, and maybe the second two every now and then has a really hard time keeping up in the grand scheme of things.
Complexity can be a sliding scale. Squeenix has historically screwed the pooch by making it -very- black and white on healers. If we just go back to the Wonder Twins plus Level 90 Conjurer, expect the same gross imbalances of the past to come back. I'm so tired of WHM being the "baby healer" just because the world outside Cure and Stone is scary.