People were way more flexible than that. As long as the PLD was willing to switch weapons and help do WS triggers they would be welcome...um people brought DRK all the time because DRK Resolution spam was awesome at the time and when you were capped you wanted it dead. SCH's were totally commonly invited if they were avail but there was just more BLM so yeah you'd make do with a BLM if you had to.
The only jobs that people shrugged off were bst and pup and I still saw people come on those. Basically a full alliance was always better than a perfect one.... couldn't find 2 BLU, well you'd take one and get someone else on something else. It was veeeery rare for an alliance that had most bases covered to not just take w/e