Mods are made for several reasons, the main reason is to put something in the game that isn't there (duh. call me mister obvious). Mandalorians (in this case) are a fan favorite because B.F. is (was) so mysterious. As LIAYD said, his armor is cool. I thought that it would be great to be able to have a troop center that made Mandalorian troops simply because they looked cool. I could care less about their stats, give them the stats of whatever civ I was playing as.
Viceroy, you play GB as one true to Star Wars, not everyone plays that way. Have you ever played Rebellion? It had a great editor that somebody created that allowed you to changed everything in it. I made myself into many characters, Jedi, Sith, Stormtroopers, Moffs, etc. The majority of the mods for that I found created super characters and super capitol ships. Why? Because you could.
The best selling point to a game is these days is the ability to make it your own and different every time you play it. The easier it is to do this the better. The more unique each game experience is the better. That's the game I want.
Of course this won't happen because then I won't need to buy another game and the game companies won't make any money, so they will continue to make static games so that I have to keep buying different games to be able to get a different game play each time I play.
Go big or go home.