No because Merged Hulk was far above the Thing in terms of strength. Remember when Drax planted him like a pole? They just aren't in the same tier to begin with, and the 5 or more minutes that it would take for Joe to ramp up would be 4.5 minutes too long.
I don't remember professor hulk ever getting stronger through anger. In fact I'd argue he doesn't. Against onslaught for example he wants to get stronger and had to have his professor hulk mindset deactivated.
__________________ Quotes from Hia8:
"I claimed that the science is sometimes faulty."
"You don't understand. This is fiction. That means none of this stuff really happened."
"There is no writer to purposely ignore a character's natural ability just because it suits the story."
"in some cases because the writer knows that Character A will dominate Character B easily and refuses to allow this to happen for the sake of the story."
When the Merged Hulk 1st emerged he had no trouble geting angry and stronger. Him vs Fixit would be a beat down in Merged Hulk's favour. MH has the same power set as his grey incarnation, with anger increasing his strength but he starts at a higher base. He is more intelligent, in addition to having all of Fixit's cunning. Joe ain't winning this one.
Professor (aka Merged) Hulk has actually all of Mr. Fixits street smarts and cunning, plus all of Banners scientfic smarts and intelligence, and all of normal green Hulks strength and power. Not sure why some believe Professor Hulk is a weak Hulk, as to me hes one of the stronger ones around. PM can basically do anything Fixit can do, and much more, so yeah going with PM to win here as well.
The only incarnations that realistically should be above Merged Hulk is Mindless and the current one. Problem with Merged Hulk was the savage side of his personality started to become dominant which is why Banner subconsciously installed the limitation. When that limitation was turned off we saw how powerful he could be when he destroyed Onslaught. Professor Green wins.