Is the default for any of the other armies not good enough for you? Gee, apparently not, because you're trying to change it. Rather silly question.
Acting as if i should care about your mod is like it's like asking a Space Marine fan to download an Imperial Guard mod. They don't play Imperial Guard, and so they don't care about said mod. They play Space Marines, so they want stuff that makes Space Marines feel better. If they get Imperial Guard stuff, too, well that's cool, but what about Space Marines? And if you throw in Orks and Tau, and Eldar too, okay that's nice too, but what about Space Marines?
That's how the majority of Space Marine players would likely feel if you discluded their faction. And that's how I feel about your mod for it not including Sisters.
Now, I'm gonna go over there to some other thread. Don't overreact to my stating my simple disinterest in your mod for its incompleteness.