Yeah, you actually have a good point in that they should remove the bottle neck for Shiva that is Ramuh and Moogle - those fights are a pain to throw together and require coordination. Shiva is, like, 10 times easier to PUG than those fights.

My advice, honestly, would be to just buy the clears, or join a linkshell and start doing favors for people. This is coming from a standpoint of: it is going to take you an extraordinary amount of time to learn the fights to the point that you will be able to have them on farm. That is a function of the fact that no one is doing them at all anymore, so, like you said, it will be hard to find other people that want to accomplish the same thing as you. While, yeah, its going to kind of suck to skip those fights, they are not very fun and the time you put in probably won't be worth the reward, imo.

It would probably cost you like 2mil to buy it knowing what I know about Balmung's mercs.