To answer your numbers question: to the best of my recollection: in the last week or so.. I have run for FC & LS people and yes, just for fun: Sastasha x4, Tam-Tara x1, Copperbell x1, Halatali x2, Toto-rak x3. Hauke x6(I think). Qarn x3. Brayflox x1.. Cutter x2, Stone Vigil x1, Darkhold x1, Ifrit (SM) x1, Titan (SM) x2, Garuda (SM) x3. Were they fun? Yep! The reward was in beating fun content with other people, including those who were new, or trying new classes. I also ran some dungeons as THM to mix things up and help some FC healers (I am very very bad at it. It could take several runs of each dungeon to get it down).
Now, all that said, if you don't enjoy a specific dungeon: don't run it. I don't think anyone bringing up fun is saying you must run dungeons you don't find fun. In fact, that is the point. If a dungeon is fun for you, you shouldn't need progression to run it. Is progression a part of the game? Well sure. In the long run in that it lets you unlock new content later. But if you don't find a dungeon fun, progression is more of a consolation prize for doing something you didn't enjoy, as opposed to being a bonus on top of something you did.
