Ehhhhh but you'd need to find someone who is a WW1 veteran as a consultant. I don't think we have many of those around anymore.
I can understand how you would assume that, but that would only be true to a small degree. Some has changed since then, but much is the same. There are a great deal of fundamentals that are sort of universal which are a constant. On top of my background, I'm also have a degree in history with concentration in the world wars period. I won't turn this into an essay, but here are just a couple of quick points.
1. No one wandered around no man's land at day time to plant mines. People really didn't stand up at all unless they were running through it to assault the enemy trench. People who popped their heads up while in the trenches would get shot too.
2. The base area is completely unrealistic. I'm skipping over the fact about the layout and contents make no sense, but if they were in the front they would be living in trench systems with underground buildings and facilities. The conditions would be appalling too, but also depending on the specific time period. It also would depend on which front it was being fought on. The Eastern front was different from any of that, the nuances are to deep for a couple of lines.
3. The feeling of it is kind of off. I get the vibe you are going for, and although I personally disagree with it, there were people there who couldn't handle it though. The overall majority of people went and did what they had to for their country and just sort of managed it. Taking days off because their friend was killed didn't happen unless they couldn't function, they would mentally deal with it when the unit was put on leave.
Again, good mechanics and good effort for the short time investment, not quite realistic though