Which is worse, trying and trying to get a perfect Luna (which means you can get good ones still but not perfect) or getting a Luna that can only be so good and useful ultimately to be abandoned because better/newer weapons come along? Stat rolls keep a weapon viable for a long long time, because you can always get a better version. Low stat statics are forever alone unless your leveling up a new character. There isn't a perfect middle ground, you have to go with what has the best return. They made this game to be a grind fest, so static guns actually makes a good chunk of that grind useless because the stuff you're getting doesn't change. Trust me I know the frustration of a bad roll but in the long run it's a better system.