Bard "buff"

[CKNovel]

the world first for tea and e12s had a physical range dps a freaking bard. know your stuff. a 10 potency increase on the most spamable ability on bard is enough until 6.0

That's not the reason there was a BRD (or any ranged) in their group.
If you paid attention, you can see that there is a 1% bonus stat for each different role your group have.

Thoses roles are:
Tanks PLD WAR DRK GND
Healers WHM SCH AST
Melee MNK DRG NIN SAM
Ranged BRD MCH DNC
Casters BLM SMN RDM

The 1% applies to all main stats, including HP and directly affecting your DPS.
Currently, if there wasn't this bonus, easy comp would play with 2 Melees and 2 Casters.

And that 1% is the only reason why all groups wants (or NEEDs) a ranged.

Apart from that, rangeds bring little to the table and that's the issue.
Look at MCH, it has a good mitigation but not enough to compete with Addle and its DPS will never match the one of a BLM/SMN.

And Sfia's group (World first TEA&E12S) had a SMN, BLM, BRD, NIN. It wasn't a lie or a mistake.
Double melee or double caster have no issues, but double ranged comp have their rDPS taxed for no reason except """mobility""" that was proved to be worthless on the most mobile tier.

As someone said:
"Know your stuff"