If the group is really bad, I will just let them wipe, but the situation is usually more complicated. I was healing an EChrono yesterday, and the party leader was someone who I know is a decent barb. The other healer I didn't know from before, but he did a good job. The DPS was good. But the casters did a terrible job, barely anything was ever CCed, caster enemies weren't instakilled, casters needed to be healed (and of course, they were never in range of mass healing), didn't remove fire walls and fogs... I also run this on my caster so it's not like I don't know what a caster is supposed to do in there. I was at 10% or so SP by the time we got to the bank and shrined, this was already a bad sign as I should have a ton of SP left at that point. Unsurprisingly, I ended up using pots.

What do you do in this kind of situation? 9/12 people did their job (everyone except the casters and the party leader who took them) and don't deserve a wipe. So I drank pots, but I wasn't happy about it.