Lawsuits Against Believers
You should not bring disputes between believers to the secular court. Matters between believers should be handled within the church.
This is an interesting idea, I like discouraging using the court system, but to forbid it is a whole other matter. What if another believer is trying to screw you over? Are you just supposed to take it? I guess the verse says you are supposed to take it to the church elders. I also don't know how the courts of the day compare to the courts of this time, perhaps it is not even a fair comparison to make.
Flee Sexual Immorality
If you perform sexually immoral acts you are committing a sin against the body of Christ because your body and his become one.
One of the problems I have with religion is that it makes people have issues with sex. Sex shouldn't be this big horrible taboo, it should be something we can have a conversation about and feel ok doing. The fact that this is so vague is bad, "I'm having a sexual desire, is it bad? Am I bad?" I don't like that kind of self questioning being encouraged.