@alidan so I started responding to you, and then it turned into a novel, lol. So I'm trying again while keeping it shorter. To start with I don't disagree with you, it's frustrating when the source material gets changed.
My objection wasn't so much about adapting the story itself, but about fitting it to another medium (it's a subtle difference and sometimes it overlaps, but here it doesn't have to). This manga is doing a poor job of capitalising on the strengths of a comic format, which is to tell the story and transmit the emotions through images not text, the result is that comics/manga can fit more into less physical space. But this manga isn't doing it very well, it's keeping all the words of the novel instead of turning them into pictures, because of the extra wordage it needs to add repetitive images that aren't strictly necessary, that's why some people were complaining that the manga is dragging on a bit which is what prompted my original post.
So in my oversimplified example I had Sei and the others make potions using the boosted plants together instead of Sei first and then the others, that's a change in the source material, but a minor one since the idea is to show that everyone's potions are boosted. If you object to that however you could have two images instead of one to show them working separately, it still would fit in less space than they did here. Similarly instead of using five images illustrating that Sei can't figure out how to do saintess magic on purpose, I used only one.
Aaaaand I'm going to stop here (it's shorter than it was, I swear) before I start ranting about publishers and safe bets, and enlarging audiences and a whole lot of fascinating stuff that doesn't have it's place here 😉