As far as enforcement goes, my views don't differ from yours much. However, I've seen how our government reacts to WTO decisions. It says jump. Our Congress asks how high. Can it enforce it's decisions. Does it have legions to command?
If we don't agree with the WTO rulings, we could opt out anytime we wanted to. But we don't want to. We would lose out on other trade deals that we see as beneficial.
The ICC, on the other hand, has a lack of carrots to go along with their lack of sticks.