I think Moon is good enough for a bench wing. I don't think the people you mentioned can match Moon's defense, so we really won't gain much with them. I like Rasho, but if we're going to splurge we should get a good 4/5.
Good players at the 2/3 are fun to watch, but unless you have someone like LBJ or DW you're not going to make the team better that way. It's more important to get as many points from the inside as we can and defend our opponents from doing so. Bargs doesn't have the high %age finish or the defense yet, but his shooting gives us depth on the wing if he plays there while Hedo is resting.
Why did the Lakers have Odom come off the bench while earning $14M/yr? Need I remind you that despite coming off the bench he was the second or third most important player on a championship team?
We're not saying Bargs should ride the bench. He should just share the 5 with someone else and spend some time at other positions because he can.