Lue would be an idiot to bench Thompson for Korver. That'd play right into our hands and virtually guarantee us a game 6 win.
If anything, I could see him rolling the dice with Korver in for Smith. You've not really been able to stop Boston's offense anyways, so you might as well bring in the extra offense/shooting, spread the floor, and simply try to outscore Boston.
Not saying that's the smartest move, but I could see Lue making that change over Korver for Thompson.