It has been a while since I posted related images in some of my replies. Nonetheless, I will leave this here:
Getting back on topic, being a time traveller sounds good. However, can we really change what has already happened in the past? Based on the time travel novels I have read, by changing the past, we could simply be creating another timeline that diverges from the original. In other words, the original universe continues to function the way it did; another parallel world is merely created.
An Esper isn't such a bad occupation either. With powers, we could try to change the world, although there will be instances where such power may corrupt one.