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

[Judge_Xero]

Is it really that big a mana issue on smn? In my SCOB static, we had rez order SMN > SCH > WHM (our whm always had more mana problems than our smn or sch, so we wanted to drain hers the least).

No, but because SMN damage is behind other classes in FCOB because of "no down time" and only short opportunities to multi-dot, players are pushing every bit of DPS they can which gives the illusion that there are MP problems.

The truth is, that even with unlimited MP, SMN would still be behind.

FCOB definitely requires more MP awareness for SMN compared to previous Coils though.

[Delta041]

FCOB definitely requires more MP awareness for SMN compared to previous Coils though.

The problem is that Summoner are solely responsible for their MP. It's similar to the white mage issue but they get 1500-2000 more MP than summoners, so they naturally get more MP per tic. Melee have to manange their TP but they expect to receive army's paeon or goad. No static with a bard is gonna drop their DPS for Summoner, and in statics without bards, Summoners are pretty much on their own.

[Judge_Xero]

The problem is that Summoner are solely responsible for their MP. It's similar to the white mage issue but they get 1500-2000 more MP than summoners, so they naturally get more MP per tic. Melee have to manange their TP but they expect to receive army's paeon or goad. No static with a bard is gonna drop their DPS for Summoner, and in statics without bards, Summoners are pretty much on their own.

Being responsible for your MP isn't a major issue since it's easy to pace yourself for a 10 minute fight with minimal DPS loss. The issue is that that DPS is already low.

Let's say that as SMN you have unlimited MP, how would you increase your DPS over other classes?

Ruin II spam so you can get in more auto attacks -> Most AA's actually get through without Ruin II spam so this would raise your DPS by ~7 with 100% up time on the boss.
Miasma II every Contagion -> (+ 40 Potency over Ruin @ 60s = 2.3DPS)
Use every Aetherflow for Fester instead of Energy Drain = Compared to using Energy Drain 1/3 of the time 9 DPS.

So now you've been able to increase your DPS by 19. Just need another 50-100

Can't really even blame it on gear. I know SMN gets shafted by Spell Speed this gear set, but overall it's a loss of like 20 DET the way that the secondary stats scale. (losing 45 DET but gaining around 60 Spell Speed) Round it up to 6 INT worth of stats and that's like a 3 DPS gain.

Edited: Just wanted to mention that the above is comparing classes close to i130, the difference isn't near that great for i115 or less.
equal classes at i115 SMN is ~20-40 DPS difference. (not counting bard)

[Havenchild]

Can't really even blame it on gear. I know SMN gets shafted by Spell Speed this gear set, but overall it's a loss of like 20 DET the way that the secondary stats scale. (losing 45 DET but gaining around 60 Spell Speed) Round it up to 6 INT worth of stats and that's like a 3 DPS gain.

Edited: Just wanted to mention that the above is comparing classes close to i130, the difference isn't near that great for i115 or less.
equal classes at i115 SMN is ~20-40 DPS difference. (not counting bard)

I disagree alot with this statement. Consistent testing I have done has considerably shown DET at current in game is quite a powerful stat on SMN. I particularly noticed what felt like a buff to it post 2.4 patch. Usually a decent amount of INT could trump even 1.5 times of it in DET but post 2.4, I have noticed a big shift in that and DET keeps showing me bigger numbers on parse when I sacrificed INT for it (assuming Im getting a decent amount of DET per INT)

Two comparisons me and a SMN friend have been making was my 19 INT vs his 34 DET and which was better. I had more crit then him and was critting MORE then him (20 times roughly).

End parses were quite similar maybe a 3-6 DPS difference on average, in my favor, using the exact same rotation, nothing different. So that 45 DET would stomp on that (60 SS + that 6 INT) by much more then 3 DPS.