To answer Guy, I suspect old Archer would see in young Archer the idealism and moral certitude that he had left behind by making bad choices and all his pain and regret would overwhelm him as he came face to face with the pure goodness that was his (relative) youth. Then of course he would immediately do the right thing, whatever that was and it would all end with..
Old Archer: Just for once... let me look on you with my own eyes.
Old Archer steps out of the time stream and stares at into young Archer's face, his own face alight with recognition and wonder. And then, because he's removed himself from the time stream thingie he collapses and dies.
Free at last, free at last..
And young Archer would be full of feelings and stuff about the need to hold on to one's true purpose because none of us are safe from slippery slopes that could lead us into time manipulations for personal power. None of us.