We stayed at the St Mary KOA in 2016. Loved it. You are parked in rows with few trees between the site, but there was tons of space. Never felt that the neighbor was on top of us. Waterton and the east side of Glacier is still one of the most memorable camping trips of my life. Epic!
I also used to view rv parks as parking lots. I am now coming to realize that whe;n out touring and site seeing for the day it is very wonderful and relaxing to come back to a full service site, have a nice hot shower, and just kick back and enjoy. Yes, when my trip involves lots of time at the campground in the daytime I like a more private stall and can get by with less ammenies!