Mindblowingly new-old idea-question that would reduce queue times for DD's

[Tyrial]

To nitpick a bit, it was more along the lines of:
Tank x0-1
Healer x1
Support x2
DD x2-3

It was never ever worth replacing a support slot with a dps. A group of 2 dps, 2 support would do like triple the damage of a group with 4 dps and 0 support because of the additional haste and such.

This was only the case really at end game (pre-Abyssea) for merit parties. Any sort of leveling party you needed a tank for, unless you were doing a BLM burn.