I don't have many positives from the first volume to be honest. The story is very untold so far, imho, so even with my apprehensions I will at least give this another volume to provide me with some orientation as to what I'm supposed to be reading.
The plot is kinda non-existent. The exposition is so high that we are told what things are and what people think, but in terms of plot, we aren't provided with any aims, goals or obstacles to engage us and be interested to see what happens next. There's a coming of age ceremony, where Will chooses the God he worships (it will surely be Gracefeel, the God of Reincarnation). The rest is still 'shrouded in mystery', of which Will informs us every other panel. For me, it's hard to be caught in the feeling of mystery when 95% of the content is explained to us via monologue/narration, and then be told the rest is a mystery.
In the beginning, it took me a while to figure out what was going on, as Will was dying or committing suicide or was just being emo. I believe this was his previous life. This was pretty lazy imo. Will's past life, due to Will having memories of it, is an important base to understand his character. Yet, we're given an intro where he tells us things are mundane, and then in chapter 3 where he decides to lament his former life again, he calls it a life of convenience. This was told in contrast to Mary's teachings and constitution, of discipline, prayer and focus, which Will found more fulfillment. I expect that Will's former life was in more 'modern' times, where things were more convenient, thus becoming stagnant (recurring motif), and that is one of the themes the mangaka is playing out. Which is a good topic for this day and age, with how people can order food to their door-step without a thought while Mary literally burns to put food on the table. There's also the first panels of the manga where Will's mind was muddied, and he didn't have any purpose or energy to put his life back on track, which is a concern these days for young people/men. However, I don't believe the manga will try to flesh that topic or any other judging by the writing style of vol 1.
Which leads me to another thing - Will and the story are spread too thin so far. Rather than trying to nail down something, Will is learning everything at a rate of knots. I'm not sure if he's meant to be a scholar, warrior or priest at this point. Wouldn't be surprised if this turned out to be a battle manga for a couple volumes, then switch into Will the monk, then President William for the finale. We've already had a timeskip.
I have written down other things which are mostly confusions or wtf's, but I'll give it another volume before airing those. There is potential for this story if the mangaka narrows the scope imo. There's also the 'living world' which we're close to seeing, which may reveal things to latch on to, plot, characters, etc.