I don't play D3, but I think at the higher levels it would drop more than just 7-8 pts if you redshirt a SO. Why are you looking to redshirt him? Is it just because he has VH potential and good WE? If his cores are too low then it won't really matter anyways. If you have a VH potential with good WE but his cores are below average then he will probably only work his way up to average. You lose points in his WE which will take you most of the season to gain back, so therefore it's a moot point. Unless it's to balance out your team then I would say you're not really going to gain anything by redshirting him.