Yeah, spot on. I was a season ticket holder for about 5 years in the Park End when it first opened. On a winter's day when people head down below to get away from the cold it is dangerously busy. Should have built it with 50% more room in the concourse area.The pinch points at GP aren't the vomitoria (had to Google that name) in my opinion, it's what comes immediately after.
In a lot of the stands you go through the exits and straight into busy queues. The worst by far is the upper bullens and Street end, the corridor behind the exits gets backed up as people then walk along to the exits.
From the plans it looks like bmd opens out significantly after those exits