Is it fun?

[SieyaM]

This is a natural consequence of Squeenix's job design philosophy. If all party comps are supposed to be viable, then nobody's exclusive capabilities are mandatory. If you make specific mitigation, debuffs, or what-have-you points of distinction between jobs, then those things will never be required/make clearing an encounter significantly easier due to point number one. The only thing that everyone can do is DPS. It's the only metric that ends the encounter faster, and the only metric that (with the occasional exception of weird boss behavior when you phase early) doesn't have a cap on its usefulness. You're basically always rewarded for doing more damage in FFXIV. That's why the community values DPS. It's the only metric that makes a difference after you've covered your bases.

Edit:
To be fair, this is also a common design problem in other single player Final Fantasy games. There comes a point where...why would you Silence or Slow an enemy? Just kill them. You can one or two shot them anyway. Don't waste MP on crowd control, etc etc.

That is what makes balancing a support class much more difficult then just raw DPS numbers, you need to make their abilities do enough to warrant their inclusion. EQ was a very different game itself, I don't remember combat following such a rigid script. Enchanters were also desired for things outside of active combat. They had mana regeneration buffs that were sought after and since they lasted at least 30 min you could get one before setting out with your group. The reality of this situation even as it is now though is that there will always be a composition that is better than others no matter how slight, and that will be what people end up trying to use. If any composition of jobs can clear content then that should be the only goal. Players will try to enforce a meta comp even if it only nets them 100 or so more DPS.