You can't just boost a class without taking into account the "end-tier" player, as well as casual. That's just fact.

Imagine a patch note where a class (no matter which one) take a 5% overall DPS increase. Now let's say that class was at 10.000 dps (with everything fully optimal, stuff and rotation) before the patch.

By taking that into account, you have boosted the player who use this classe extremely well by 500 dps. But what about those who don't master the class this well, or don't have optimal equipment ? Of course they will gain 5% too, but 5% of a lesser value, in which case the gap between good and bad player will be growing wider.

In order to make adjustement, it's necessary to take into account every kind of player, otherwise it can make absurd tweek on classe that will lead to a class being unplayed, or Overly played because it's completely broken.

As for the utility of classes, I have a different point of view, especially about RDM/SMN. They have a Raise spell, that's a huge support to begin with, as it allow your healer to keep their mana up in case they have to heal through a raid wide damage or any other mecanics encountered by the team. Maybe you do lesser damage overall, but you have some "insurance" that allow you to raise one of your party member almost for free. A raise on a healer at a critical team, so he can LB3 heal right after to make everyone on their feet, this can be a complete game changer, where a BLM wouldn't be able to do that and just witness his death, forcing him to redo the boss till the beginning. I've seen countless raid (Either Extreme or Savage) that were saved by those raise.

So for the question : Does utility mean less DPS ?

Answer : Yes. Otherwise, All classes of the game will have the exact same potency on each spell and all the DPS will look the same. This can be true for Healer and Tanks as well.

Utility does have it's role in affecting DPS on classes, but I think that the complexity of a classes should have a role in that Too. MCH is extremely easy to play, You have plenty of offensive stuff and mobility that allow you to move freely wherever you want. You even have 100% Uptime (In Theory) because you can attack up to 25 Yalms... Many thing must be take into account before buffing or nerfing a classe