This idea will most likely be chaos incarnate if done correctly. I want, in this idea, for Touma to be a godly entity, (unrelated to the magic gods), or alternatively, someone with enough power that they could be considered a god.
I want Touma's personality to stay the same for the most part, but maybe make him more prone to causing chaos outside of just his own misfortune, for like amusement on the side of being heroic or something. You can change up canon however you desire; I'm looking forward to it.
Definitely don't take the route of everyone praising his power or anything like that, though. Make it so that everyone is mostly just frightened and/or confused. Don't remove Touma's Imagine Breaker or the Invisible Thing, but somehow, despite it being against the rules of canon, I want you to either give him an overpowered esper ability or an overpowered magic ability in addition to his usual powers. I'm not going to tell you what to make this power, since I want it to be surprising for me. Try to make his new ability in line with canon rules, but if you can't then you can't.
If you actually make him a god, then stuff like Aleister Crowley's plans, Aiwass, Othinus, and the other magic gods or just the magic side in general, all need to have their positions in the story reworked. You'll also need to give Touma multiple new abilities, and have them be unique as well.