While I understand the frustration, if this wasn't a new healer and they refused to use Esuna. I highly doubt it making it a mandatory thing would have made them do it. If it's not on their hotbar already, they probably wouldn't have used it anyways.
I'm not disagreeing it should be mandatory, but in this case..it seems like you got a jerk healer. Who would probably not use it on you just to spite you even after asking for it.
I think what they might end up doing is splitting the role actions into two sections. One that doesn't allow you to remove them and others that you can adjust. This role system is the tip of the iceberg that could have some potential. In the future they could expand on it and have Protect / Esuna as mandatory role actions but another section of 5 slots for "optional" and increase the amount of options.
If we don't remove it, but adjust it..we get the same result. Esuna is made automatic and mandatory, and...the healer still can choose to not use it.
I'd much rather have protect get an increase like it has in PVP before removing it. Yes so far it says it's for WHM only, but to adjust it so that it can be used for all jobs via their gauges would make it interesting to use again. Adding this kind of resource to most actions would be a possible welcome change, or an unnecessary complication...whichever.