Interesting points you bring up. Thanks for giving reasons why, instead of saying "don't do ab work."
I actually hadn't done any direct ab training in a while. The first time I did it (two days ago) I noticed the muscle strain was a lot worse than before the workout.
I don't do much direct arm training, either. I don't think 2 sets a week are going to do much damage. The program I'm on doesn't call for too much arm training, it just happens to be in this particular cycle.