Let's talk about the theory of GCs

I do understand but it is still the exact same. If it is most easily completed by the faction the only "challenge" is having that faction built up. The challenge in most galactic challenges when it comes to the faction feat is that you are usually at a disadvantage with that faction, you then need to work out the puzzle given to you (e.g mods, line up or strategy) to get the Max rewards.

This is like saying in a jedi GC, it would be most easily completed by having JML, JKL. But you CAN beat it without those characters.