I could by Pokemon Ruby and then the updated Pokemon Emerald and not give it a second thought. Mainly because the newer version doesn't make the older one completely obsolete, and it benefits me greatly. But a double version of something like this just wouldn't go down well with most fans. Especialy if they are released just a few monthes apart. Now what if Nintendo decided not only to up the game with rev-functionality but improved graphics as well on a seperate disk that came with the original game? Something like that I wouldn't mind one bit. But if they released 2 versions of the game at full price I would be quite angry.
Now about this new violent fighting system I don't think it will be so bad. At the end of OoT and WW, Link attacked in a way that was pretty brutal but even that wasn't so much of a big deal. Mainly because there was no blood in WW and... well it was the blood in the origonal Oot and that made it kind of gruesome, kind of. Either way I expect to see more finishers like that with mini and big bosses. After seeing Link in Soul Calibur, I can't really think of much that would be over the top. As long as blood isn't spilling from enemies excessivly, and Link doesn't go around removing heads from the more fleshy enemies it will be fine. Any type of skeleton or plant monster is one thing to decapitate, and we have all seen it befor, but a Moblin? No no no...