I just think the MC isn't ready. Neither with his magic nor socially or politically.
I disagree on his magic. He's already far above average when it come to combat. The average mage is probably close of what we see with Persus, the teleportation specialist. He cast a couple wards, a spell like the magical pit, and he's out of juice.
The MC? He can sling fireballs all day long, or close. Already, that's quite powerful. And he has his Firestorm that can overwhelm most magical defenses. And he can move really fast due to his Spark. Add the illusion, and another ace in the hole not shown yet (the update after the next one), and you have what is a very powerfull battlemage. But, the other mage that is the most often shown is Athagan, and he' s OP.
No, only the really heavy hitters or surprise can get to him, really. A mundane person without magical defenses is nearly powerless against him, with a few exceptions like Sariel. And even the strong mages need to be very careful...
Now, what he doesn't have yet is versatility. He has nearly no utility spells, except for remote wards, and if he is one day against someone or something immune to fire he could have a hard time.
But you are spot-on when it comes to diplomacy. If he didn't have Athagan backing him up he could have been in hot waters. But he'll get there. I already added some of it to the story. To his defense, he just can't stand an asshole, but he's very good to decent people. It's just that he has a hard time to think of the consequences of his actions. He goes for what is right, damned the consequences. He'll have to adjust, or beomes so strong that it doesn't matter...