not close to Morales and Barrera. They are much greater, and he had a good style matchup for Manny, who is much better also. Marquez is below all of them. The outclassing Mayweather gave him showed something.
so if morales or barrera fought floyd at 145 would it be any different, marquez's performance vs floyd was a better performance than barrera's vs amir khan, so what did that show. fact is that marquez beat barrera, and when you compare fighters they both fought, eg pacquiao, then its clear to see that marquez is the better fighter, barrera had hell for 2 fights, wheras marquez gave him 2 boxing lessons.
agree with you that if he conquers 140 then there can't be the question if he is greater than morales and barrera. if he does conquer 140 then with the quality of opposition in the division i can see him being ranked in the top 2 of great mexicans with chavez sr, personally i would rank marquez above because im a fan but i would expect most mexicans to choose chavez sr.