what are we complaining about? there are so many isekais that almost everything could be considered as a trope... personally i read it as i would with fairy tales... i know there is a prince, there is a princess and they will end up married somehow. The MC is a kid that only knows his mother and his brother because for 15years he lived in isolation, studying magic or training swordmanship with his brother who doesn't really know much about magic... if a normal kid was to be raised like this, his social skills would have been terrible.
He is a 15years old boy and he's going to the academy... He is fleeing because he already showed too much and he thinks that being targeted/labeled as hero will be troublesome, BUT, you know... he wants to do the right thing out of pity but still not get involved too much...
Why a sage of his caliber doesn't tune his spell better? well that's for comedy, character and to show off. You know... it's a manga... if i want to read something more... a book is more suited to do the job. This type of mangas and LNs are just there to milk the genre. If they have a good reception, the author will try to write something good/better, if not, they just deliver the chapter... furthermore when you are writing a book and you suddenly have an idea about your story, even if it is when most of the script is done, you can change things around and create a better story, you can't do that in LNs and mangas, they are delivered most of the time one chapter at the time with weekly or monthly releases.
