It was the best way to keep the character dead and have him back at the same time. And this Red Skull can work better as a villain because his mind is the same as it was in World War II, back when he was still a racist Nazi with all that burning hate for anything different (and entering the modern age of mutants with no warning or build up). We need to have villains that we can still despise, because lets face it too many of the popular villains are becoming likable to the point that they're going good (ie Magneto, Dr. Doom, Galactus, there's even a good version of Apocalypse now (not referencing the Coppola film, that was gold and the pun wasn't intended before it was on screen)). Loki probably has more fans than Thor by now (myself included). If we don't get more of our A-list villains to act like A-list villains, we're stuck with the likes of Trapster.