I could see Thurman vs Canelo being boring if Keith didn't engage, but I'd favor Canelo via decision.
I actually think Canelo would've KO's Spence just due to size advantage and styles. Spence is a very come forward fighter and Canelo is an excellent counter puncher
I think that 152 pound drained Canelo KOs Thurman with hard body punches and then head punches but loses to the relentless and tireless Spence. Today's 160 pound Canelo is much better than that version of himself. He would KO the Mayweather who beat him and any other boxer below 160 in my opinion. Only the best 2 or 3 middleweights have a chance to beat today's Canelo.