I don't think McCourty's a safety. I think the off-the-street corners they've brought in have just been better than the off-the-street safeties and the Patriots found a way to maximize the talent on the field.
I think McCourty could be moved to S, and that would probably be a solid move with Ras-I coming back and having a nice group of corners in the late-first, early-second range (Minnifield?).
Also, from what we've seen, I think Edelman could make a legitimate move to mainly CB with a full off-season and I think he'd be really good there. He's got the size, quickness, tackling, and speed to do it.
Even if you do move McCourty to S, it's still a high-priority draft need with the injury issues Chung has dealt with his entire career so far.
I think Edelman could be a great receiver, but Brady's timing with him is just off for some reason. I just don't get it. When he's in the slot, he's just as good as Welker. But put him outside with Welker in the game, and Brady over/under throws him every time.