Can someone give me an in-depth explanation why Summoner is arguably the worst DPS?

[SomnusNemoris]

Ah yes, of course, lets greatly nerf the other casting class, so that melee can truely dominate any dps spot.

5min cd flare, would make BLM weaker than SMN in both aoe and single target imo, which I'm sure is what half of the people here want, but all that does is make casters in general ever more sucky then they are now.
This sums it up very well imo, I suspect many of the people complaining for extreme changes are not doing end game content and probably not pushing their class anywhere near it's potential.

It doesn't, though. First of all, if you actually compare the BLM DPS chart with the SMN one you will find:
MAX DPS BLM T10 - 583 | Max DPS SMN - 514
MAX DPS BLM T11 - 543 | Max DPS SMN - 495
MAX DPS BLM T12 - 543 | Max DPS SMN - 504
MAX DPS BLM T13 - 515 | Max DPS SMN - 492

Even in movement heavy fights such as T11 and 13, BLM still outshines SMN. You honestly think a small buff will fix the problem? Not to mention that Sen his own DPS is far behind was really good BLM do. I don't consider myself a super BLM, but I outDPS him by 30 at least on every single turn. What small potency buff do you have in mind? One where you still are behind BLM in AoE and ST damage aspect? (Also note that Somnus is my alt)
I think from these numbers, it is crystal clear, that SMN needs more than just a small buff and an MP fix.

What else can we deduct from this?
T10 should be more of a SMN fight with the Bane. But as it shows, the difference is 70 DPS. Which over a 10 minute fight is like what? 70*60*10= 42000 damage extra. This in a fight that is mostly single target and has perfect conditions for SMN.
T11 is a complete ST fight, as a SMN you can actually also dot other stuff. Yet BLM triumphs again. So, movement heavy fight, targets that can be dotted and yet BLM still wins
T12 A lot of AoE, BLM should reign surpreme and so it does. Although it must be said that baning those Benus can be pretty sweet too. But overall BLM should win on this fight and so it does. I have seen BLM do more than 543 DPS as well.
T13, can be a bit of movement with earth shakers and AoE is favourable for both. Especially since you can Bane the Storm and little dragons and also the final add. It's movement heavy so overall I think SMN should have the edge, but only by a small margin. Yet we see that BLM has the advantage, even in a rather movement heavy fight (potentionally).

Can we please stop pretending as if Summoner is close to BLM? It is outshined in ST, AoE and utility departement.