Golovkin is now too shot and inactive for a prime, strong, young Tszyu. Don't think some people here realise or want to admit how good Tszyu is.
Timmy stays at 154 for another 3 or 4. Then moves to Middleweight. If GGG is still around then, he'll be a prime target. If they fight, it will be King Kostya versus Julio Cesar Chavez all over again. Great fight if you're a Tim Tszyu fan. Not so much if you're not.
Tim is still not in his prime and GGG is past prime since years. It could be interesting. But can GGG still make the MW limit ?
I don't think GGG will ever fight again. If he still has enough left in the tank I think he'd beat Tim. But slow, shot versions of fighters rarely do well against fresh prime dudes.