Hercules would be fun. It would sort of be like giving Thor a big brother type making him sort of like the Jan Brady.
obviously not his literal brother but in terms of character dynamics
That would be nothing like what long time fans of the Herc/Thor dynamic would want.
Their relationship is way more like the rival quarterbacks of two football dynasty type teams. Or to put it in another sport's terms, Thor is Magic Johnson and Herc is Larry Bird.
Both have definite similarities which they bond over but their personal journeys as hero gods diverge a lot too making them unique. When together they bring out both the best and the worst in each other.
For me an issue is that Thor as he developed in the MCU is a lot closer to comic Herc than comic Thor. But... That could work. I kinda always assumed Thor stood just a little taller, acted a little more serious, played down his lusts and appetites whenever he shared the room with Hercules as Avengers.
"Hey... I like a good bacchanal as the next god. I drank the ocean halfway once after all... But I'm not some drunk frat party boy like THAT guy! He's the prince of his realm but he acts like some fool at a bachelor's party!"
And Herc's take is:
"Look at this pretty boy who thinks he's better and STRONGER than me! Acting like he didn't party hard back in the day! Plus... He grew up a prince with daddy and mommy giving him everything, grooming him for the throne. I didn't meet Zeus until I was a man, and he's still on my case! I was raised among men. I'm from the streets son!"
Now, that's the comics.
In the MCU though if they use Herc alongside Thor as we last saw him maybe that's a way to get Thor back into the groove and off the sauce. Have him recognize that he's gone a little bit over the line in his tom foolery and indulgences by looking at a guy that is an immortal party animal.
"I like this guy but... I am not sure I want everyone around me to think of myself the way they think of him... Hmmm... Maybe it's time to put down the booze?"
If anyone wants a good take on Herc and Thor's relationship from the books I highly recommend INCREDIBLE HERCULES and the arc where Herc and a Zeus transformed into a boy (Long story...) go to Asgard and Herc pretends he's Thor' costume and all.