If, you actually watched Wagner play last year, his stats were much better than his play suggests. He can't run anymore and his game is totally dependent on his great instincts and experience. He had 140 tackles but most were 5-7 yards to field. He had 140 tackles but, partially because he could not get to place in time to keep the runner from converting 1st downs. That gave him more opportunities to be in on tackles.
At this point, I would take Leighton over Wagner all day long.
Leighton can cover more ground and will be in his 3rd year with Dan Quinn. My only concern is Leighton's ability to stay healthy.
If, you think I'm full of B.S., he was a free agent and any team could have signed him and a 1 year $7 Million contract was the best he could get.