Someone was saying this on the most recent AFCB podcast -- it comes down to, are the wingbacks "wingers" or "defenders"? If you play wingers as WBs, you will tend to end up with more of a 3-5-2 formation, but if you play defenders then it will tend to be 5-3-2. The exciting thing about 3 at the back is that it can turn into "only" 3 at the back, with the other 7 players attacking in one way or another. So it has the potential to be one of the most attacking formations ever. But it depends on the personnel.
Stacey and Smith are both defenders, so we've seen things necessarily more defensive-tilted.
What about Zemura on the left and Stanislas on the right? That would be interesting.
You need a very solid back 3 to do that though.