MACO set hands down. But i always craft the aegis set when im leveling a new toon, purely for the prestige of having a very rare level set all the way up to endgame.
I thought i had a similar problem while filling out omega projects, the server lagged and i had 2 of the 4 required items only half filled. I just replicated more and was able to finish out the project.
Completely agree with the op. There is absolutely no way that an elite setting stf should be doable with no less than 5 players, and that's not even including optionals. This is supposed to be the most challenging content the game has to offer. It's high time for cryptic/pwe to make elite stf's ELITE again.