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

[scarebearz]

I understand your posts perfectly and if you think that BLM will come with higher numbers too, that negates your point

It does not negate my point at all, I believe we will see bigger increases in the SMN chart than we will for the BLM one that has been around longer and has much more data.

I agree the gap between casters and melee is a bit big, but it is not far off what it should be imo.

Back when most static slots for t9 were filled with SMN and people were making a big fuss about BLM being weak, BLM got around a 6-8% buff and I do consider that to be a small buff.

Decent players were still doing very well as BLM dps-wise and it was fine for meeting the T9 dps-checks back then.

On content were MP is not an issue (Ex's, BCoB, SCoB), some SMN still seem to do very nice damage and the gap appears to be much smaller, though that is from personal experiance only.

SE are pretty good with class balance and before long SMN will be adjusted, pretty sure they know the actual difference in numbers and will fix it (like they have done with other classes), but it won't happen over night.