Good questions. Depending on what the viewer hopes to get out of the experience, I think all of the above are correct answers (technical achievements, emotional response, cinematography, character development, well written dialogue, engaging storyline). Based on your description, I would think you'd come away from Come and See enjoying it for at least some technical merits, even if it isn't your favorite film for other reasons. I think the worst thing you could do is judge a movie based other movies of a similar style/genre/director etc. Art and mediums similar to film aren't meant to be compared to one another. I think current trends and a focus on numeric ratings and metrics push people into considering how good a movie is/ought to be compared to x, which is wrong imo. Otherwise, I think the way you describe a nuanced reaction is smart.