I will try to answer all of your questions based on what I have seen. My take is that BYU more than most programs looks at placing/wins more heavily than pure times. This may in part be due to the challenge of comparing altitude to sea level times for HSers, but I think it is mostly part of the overall philosophy.
If you are a 4:12 state champion then you are perceived as much more of a stud than a 4:12 runner who took 6th. They want to recruit winners and I think that tells you as much as anything about what their team culture is like. I know more than a few people are put off by Rory's ego, but the culture and coaching staff if anything sustain it more than trying to bring it down.
This goes into the next point. Is it a meat grinder? No, not deliberately, but there is an atmosphere of interteam competition and just competitiveness in general. The coaches to try to keep everyone healthy and the training isn't designed to run people into the ground. However, I think one of the underlying factors leading to the team historically looking so strong early season and then fading a bit towards the end is that workouts are competitive and everyone is running a bit too hot too early. Not dramatically so, but enough that it can impact results for some individuals.
The coaching staff is very engaged and I think that most people feel like they can get individual attention if they want it, but it is a busy/crowded experience just because there are so many guys.
You didn't ask specifically, but I will say that their culture is unusual relative to most teams I have seen in that it lacks a certain friendly and open vibe that running typically engenders. My perception is that runners tend to share a bit of a shared suffering culture where once the race is done, everyone feels free to mingle, catch up with old friends, and there is a sense of broader community. I ran at a different university and when I was home for winter break I often ran with old teammates and friends who ran for lots of different schools. It wasn't uncommon to go do a cool down with someone from a different school and get to know them. To me it seems like for the most part interschool sports rivalries don't really trickle down to the cross country teams, even if the football and basketball teams hate each other, the runners don't care.
BYU does not embrace this. Their team culture feels as though it embraces rivalry, competitiveness and just a general us vs them mentality. The positive spin on this is that they have a lot of school spirit and are very unified. So that might not necessarily be a turn off, but it is something to know.