Maul should have survived EP1, he was bad ass and should have been the main villain.
No, I don't think he should have survived. He served his purpose - namely being an explicit menace that was quickly dealt with, leaving the real menace hidden in the shadows, confusing a monolithic Jedi Order that was unable to adapt to the real threat. It's no accident that Palpatine took control by subterfuge and no real brute force on his part, or those of his disciples - employing a callow youth and a past-his-prime fallen Jedi to deflect attention away from himself until it was too late. It underscores how out-of-touch and rigid the Jedi have become ... too beholden to their "Code" to see the real threat ... until it was too late.