Not to beat a dead horse/swing the whole thing back to the tangent I was on a few pages ago, but I was screwing around in Abyssea last night and reminded myself that if anybody is really at a loss for an example of something for which DNC soloing is particularly useful, I'd submit cruor farming, since we now ought to all have more stones than we can ever spend so farming without TEs ought to not be such an issue.
Cruor chains aren't hard per se, but after a few unremarkable cruor party experiences I'm pretty comfortable saying the specific order of kill one, then the other, then the first, and keep this going for hours and if you screw up you start over again, is too much precision to really be worth doing in a party.