I've got a Winesap tree that I bought from a big box store 4 years ago. It hasn't really grown at all since, as I've had to cut back the central leader due to dieback a couple years ago. Nothing has grown well enough to take it's place. This year the branches left on it only grew a few inches, but a root sucker put on 5 feet of growth!

I'm thinking I should cut off the old trunk down at ground level, and graft a new Winesap scion to that new root sucker, rather than cut off the sucker and hope for a better result from the old tree.
What would you do?
Has anyone tried this before?

I'm thinking I should cut off the old trunk down at ground level, and graft a new Winesap scion to that new root sucker, rather than cut off the sucker and hope for a better result from the old tree.
What would you do?
Has anyone tried this before?