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

[Odowla]

Point is, utility skills are valuable when you use them every single time the are off cooldown, and in the case of virus when antibody is not present.

Both Aikaal and I just said, WHM and BLM Virus is equal to SMN Virus on Adds. There's ONE add in FCoB that does magic damage. ONE. Supervirus only lets virus affect magic damage. Sooooo... pretty much SMN virus = BLM/WHM Virus. There's also ONE add in SCoB that does magic Damage; The Ghosts of Meracydia in t9. And the damage you'd want to virus is unmitigable, anyways. BCoB doesnt have any that I can think of. So yeah, tell me when Virusing an add as a SMN is better than a WHM or a BLM?

E4E is unreliable, though - you could have it up for 3 minutes straight and have it never proc. But yeah, its a great spell, right? It COULD be useful.. but again, WHM and the BLM can have it, so it's not like SCH + SMN is > SCh/WHM/BLM by any significant margin, even considering the RNG aspect of E4E.

Surecast is great, actually - there are some hits that you get interupted, and using Surecast prevents that.

Blizz 2 has its uses, albeit not very many of them.

BLM has actual Unique Utility though; Manawall/Ward/Apocatastasis are unique in function and are exclusive to BLM only.