Ginn is intriguing purely because of the tease of being a duel threat of returns and catches from Brees (he'll be running Brandin Cooks routes but without the hands). I wouldn't be that excited that he'll put up stellar return numbers. He'll be switching from a non-dome to home dome stadium, so touchback % will be a concern. He is moving within the same division (with kickers with good touchback %). I think you can expect his return yards last year to be his baseline/ceiling for this year.
Solid sleeper picks for return yards are slim, but here is my list: