It's odd, I don't mind seeing an old Luke and Leia, but I really don't like the idea of seeing old man Han.
Because it's a horrible idea.
Which is funny because of the three of them Ford has probably aged the best.
He has, true. But, I don't want to see Han Solo as an old man. There can't be anything but tragedy there. Either he's a burnout, a man child, or a camp version of what he was.
Solo is the type of character that burns out in one epic moment of redemption. He doesn't die of old age.