I disagree, Reasons why:
Tre is a top 10 CB in the league in the prime of his career and is only 27. Woodson moved to S only when he went to Ravens at age 34.
Tre only weighs 180 lbs. And as you noted, is not a sure tackler. Not ideal traits for a S in Bills D.
Tre has never played S in our system. Several of the young guys, Lewis, Neal, Benford have seen reps there.
Hamlin has looked good to date and possesses ideal size, tackling and coverage ability.
Benford may be the guy to move given size (6', 205 lbs), tackling ability and demonstrated ability to learn the system. Personally I am good with Poyer and Hamlin at S and and encouraged by the surplus at CB we will have once Tre get back. Tre and one of Jackson, Elam or Benford at outside CB. With Taron Johnson and Cam Lewis to play slot.