It's worth the try, many of those who disregard help from other players could probably accept it if the help isn't coming from other players.
I understand what you are getting at and i agree to a extent, but i find that the "lazy, it's my sub i play how i want, ect." excuse does not apply to everyone, it's just the go-to excuse that we assume is the reason that these types of players use when we see someone with a odd play style, such as the one i mentioned in my OP. There honestly might be those out there that just don't know or just didn't read over their skill tool-tips carefully enough and they just need the knowledge. I think it would be beneficial to have a system in place that acts as a pseudo-tutorial that at least tries to teach these players the difference between aoe and single target abilities, as for if these players actually make use of the knowledge....well that's a different story entirely. Then it would fall on us, the community to try to help these players out and if at the end of the day even that isn't enough, we can all say we at least tried to help them.
I'd like to also propose the inverse of what the OP is asking for: some kind of training to tell tanks why mass pulling at level 15 is (depending on your DPS classes) a complete waste of time. The fact that I see this with like a monk and a dragoon in the party tells me that many tanks have no actual understanding of why mass pulling is even a thing.
That's probably a sign that the tank should slow down, people seem to think the tank controls the party, when in reality they don't, it's a group effort, the healer is usually needed to keep the party's health up, the tank is needed to keep the mobs from killing the rest of the party and the DPS is there to support and kill the mobs. Just because people don't want to AoE doesn't mean they should have to. Some people like to take it slow and aren't in a rush to get to the next dungeon, raid, or whatever.
It's not even that. Monk aoe currently is really bad. Not using rockbreaker is pretty bad (and not using oGCD Howling/Elixir is even worse) but I totally can understand MNK players who opt to aoe quite little even on huge pulls... because they don't have good means to rotationally aoe. Thanks to oGCDs, their aoe damage is still ok but comes in spikes.
What I would LOVE to see is the intermediate hall of the novice like HyoMinPark mentioned but with player competing against himself. Making him to do duty with only aoe skill/combos available first and then the same but with ST rotation and telling the resulting time after. And pit him against 5-10 mobs or so.