Many people would want that. I still have the GameCube version myself, so I can't say I really need to play it. But I'm mostly interested in Spawn of all characters. The problem is that Link is Nintendo exclusive. I think the SC2HD version was meant to cut off any exclusivity the original console releases had. So no one could have the "better" version. Though with that said, It would have been a smart move for Namco to make a Wii-U or even a 3DS version of SC2, with Link, Spawn, Heihachi all on the same copy of the game.
Too bad SC2HD has bad netcode, which is weird when Namco has done such a solid job with SC5 and Tekken Tag 2.
As for Lost Souls, it was rumored that Zasalamel would be in it, based on one of the trailers showing his SC3 cutscene. So if he's in, and that might be kind of a big if, I would be interested in it. There was no reason for him or Talim to get axed out of SC5, since they had original fighting styles.
EDIT: Double post, my bad.