It's the lack of certainty about having effective and engaging gameplay.

Basically, all the responses about the changes to Healer DPS skills and the pruning down to a bare minimum of a single DoT and nuke skill is due to the concern from the fact that currently, Healer gameplay is 80-90% just DPSing, thanks to ridiculously overpowered oGCD heals and predictable damage bursts.

In this scenario simplifying DPS rotations means simplifying how a Healer spends 80-90% of their time.

If it happens that damage is increased so that Healers spend more time Healing and less time DPSing, that would help alleviate the issue - However, this comes with caveats, such as if damage is so high that you're forced to spam Cure II/Benefic II/Adloquium on the Tank to keep them up that won't feel engaging as that's just mashing the same heal button ad nauseum (To say nothing about how it would feel for a Tank to be so heavily reliant upon heals) as well as the fact that we've no indication that incoming damage will be increased (If anything, the new Tank trait means that damage is being decreased as far as we know...)

This of course, doesn't mean that Healers necessarily need to be balanced around "Dealing Damage" vs "Healing" or that Healing necessarily needs to devolve into spamming your "Big GCD Heal" over and over.

There are alternative ways to increase interactivity with Healers via alternate means.

Such as creating more interesting Healing skills.
For example, instead of just pressing Regen and applying your HoT, what if you had to use a combination of skills to apply your HoT. What if "Freecure"/"Enhanced Benefic" style traits were made into actual guaranteed gameplay mechanics that promote using your smaller heal to access a larger heal (Or one with additional effects). Etc.

You could also allow Healers to do more buffs and debuffs.
This need not necessarily focus entirely around rDPS buffs. For example, being able to buff a Tank with 10% damage reduction is essentially the same as applying a HoT to them is it not? Maybe you could bring back skills like Apocatastasis *Cough*Shell*Cough* and Palisade *Cough*Protect*Cough* for Healers to use. Maybe Healers could be the ones to get things like Addle, Feint and Dismantle. To protect their allies by reducing enemy damage output.
Also, while it may currently be Dancer's "Thing" to be about buffing allies, why can't Healers still also have interactive rDPS buffs? Like what if Chain Stratagem was needed to be maintained by Scholar via GCD's inbetween their healing? What if Astrologian's Cards where interacted with via GCD's between their heals? What if you actually gave WHM something other than just increased potency numbers?

These are merely examples. But the core problem is that Healers want engaging gameplay.

As the game is currently designed, we have no reason at all to expect that ShB will evolve the current combat systems in such a way where this Healer design with neutered DPS rotations would be anything other than a direct downgrade in healer interactivity.

Which is a problem, given how little interactivity there already is with their current DPS rotations due to the current combat systems, where predictable damage and ridiculous oGCD's effectively restrict the amount of actual input needed for effective healing output.

TL;DR:
While many players are complaining about the neutering of DPS rotations, the actual problem is caused by a concern about a lack of engaging Healer gameplay. Healers need to have a more interactive role in the game other than waiting around playing "Simon Says" by responding to scripted damage via the push of an oGCD button.