Yesterday I did some testing on how it really is like to only heal in expert roulette, which I think is a good example because it's content probably ran by majority of player base this discussion is relevant to.
I queued to expert roulette as WHM and we got Xelpathol. In addition to me, the party consisted of a WAR who had never tanked the dungeon before (no endgame experience as WAR), a BLM (his Savage job, currently on A11S progression), and a DRG (no endgame experience as DRG). So quite a random party composition with people more or less familiar with their roles in that dungeon.
The WAR pulled as much as he could at the time (not knowing the dungeon as tank he failed this a couple of times) and I would only use my healing abilities. This was the result, my every single heal cast for the whole 21 min dungeon run:
- Regen x24
- Medica II x16
- Asylum x7
- Assize x4
- Cure II x5 (between pulls, not during them)
- Tetra x4
So in addition to Medica II, the only thing I actually had to cast in the whole dungeon was Cure II, which I did a total of 5 times (
between pulls, not during them). Everything else was instant cast abilities. I also used Eye for an Eye on tank and sometimes Esuna, and I cast stoneskin on everyone between pulls.
Even with this little use of healing, my overheal was 35,9%, so the actual healing requirements for this dungeon are even lower.
I was active 17% of the whole dungeon while the rest of my group members were active 72-77% of the dungeon.
This is a perfect example of the low healing requirements in the game and how it causes a huge activity difference between a healer who doesn't DPS and their group members. On that run I did not contribute nearly as much as my group members, in fact I was using /icam and doing /mandervilledance while they were actually making an effort. If it would have been the tank or a DD only being active 17% of the time and dancing and idling for the rest, they would have been removed from the party, but for me, some people would actually argue I was doing just fine.
I took a video of the whole run and uploaded it in case someone's interested. This is the final boss fight, during which the only things I actually cast were 3 Medica IIs. Other than that, I used Regen (4), Assize (2) and Asylum (2). Here's the direct link to the fight: https://youtu.be/jBgMe5uHPsE?t=17m17s
TLDR: Not DPSing as a healer means you're just being carried by your group members for over 80% of the dungeon time.