How about a non-support ranged dps?

[RiceisNice]

Not who you asked, but the honest answer is if all DPS was equal, you would stack 4 ninja. They have the best overall party support with both the slashing debuff helping tanks, and trick attack helping everyone. Rotate the CD properly among the 4 NIN to get a constant +10% damage. They can also provide regen for sustained fights, Goad still being a thing to provide the TP boost to the tank and the other NIN.

So the answer is, in a world where all damage is equal, and you don't get a LB penalty for stacking classes, go 4 NIN in DPS. Best overall support, and better overall party DPS.

Except, you have a warrior for slashing debuff, you have no regen for healers, no foe requiem or RoD to boost healer damage, no STR bonus for tanks, and of course the obligatory reduced LB charge. Would the increased uptime on the 10% debuff be enough to win out on foe reqiuem, the loss of STR on tanks, and the reduced LB charge?

That's also not getting into issues with positioning for mechanics like lightning storm or sluice.