Re: Herc cameo?
Resurrecting this thread for a casting suggestion - how about Joe Manganiello as Herc? I could see that working; I mean visually, he has the height and build to be not only a great Herc but also a good physical match to Hemsworth's Thor.
Sure, there'll no doubt be negative shouts about his acting ability but I think he's be able to hold is own in that department too.
Don't be ashamed of the source material when making your adaption. EMBRACE it.