considering Red already walloped a Watcher, disgracing the poor guy in the process, Thor stands zero chance of matching up against him.
bfr is the only thing he can do, probably banish him to some dimension that Hulk was banished to by Strange.
realistically, in the comic, I expect Thor to be swiftly overwhelmed and defeated. leading to a Savage Hulk/Thor team up against Red, which (hopefully) ends with King Hulk re-emerging and smashing Red with some corny "I'm the strongest one there is!" thrown in for good measure.
Hulk, in all of his pre-WWH incarnations has always given classic Thor a good fight. But I really don't think Loeb properly handled Red Hulk well. His power level is consistently higher than pre-WWH incarnations... but the way he handled his fight with Hulk and the ludicrousness of the whole Watcher scene just pisses on the idea of suspension of disbelief. So even if Red Hulk is really that powerful that he could give current Thor a good fight... NOBODY will ever believe that Loeb could properly write a fight between the two. Either Loeb's Red Hulk sucks or he has no grasp of current Thor at all. I swear, if WWH fans had anything else to turn to and if Thor wasn't appearing as a guest, this series of Hulk would have been cancelled long ago.
Current Thor 8/10. Only if he decides to go mano-y-mano. Any depiction of Odinforce Thor doing any worse will make me puke in my mouth.
dunno how strong Uatu is, but clearly he isn't tough enough to take a couple of punches from Red... which is pretty stupid but, if they truly do want to make Hulk "The Strongest One There Is!", the way to go ...
anyway, there's a difference between being a non-interventionist and being willing to suffer a savage beating (which is what he was in the process of receiving from Red).