So elemental resistance/weaknesses would be bad, but AoE limit break is fine?

If I understand correctly, the reason given for not having elemental resistances is because some jobs would end up preferred (required) by players for content. There would be situations where people would just refuse to do content without whatever job that had the ability that was strong against whatever.

So, last night I'm doing hard mode Ifrit in the duty finder, and like three runs in a row end up with no BLM/SMN in the party. While it is technically possible to complete that way, it seems much more likely to end in a wipe since all the DPS need to be coordinated. Having the AoE limit break makes the nails an absolute joke, like the easiest part of the whole fight. I don't want to be one of those people that just drops if there's no AoE, but I also don't like feeling like I'm wasting time doing these runs and failing just because we didn't have that job.

So rather than use the DF, just find a group of 8 people to do it. IFrit is a 5 minute job for the right geared people, just go in, and kill em.