the design of the North is not a mistake...it's deliberate (imo, of course). Why? See below...
....because Tony doesn't want a "kop"; he prefers the gentrification of football. .
Totally agree that the design of the North Stand was deliberate (hard to imagine how it could be accidental!). But I'm pretty sure it was a lot more to do with a design that could achieve planning permission than some desire to prevent too many people from sitting behind the goal. The stadium was built to fit into the natural slope of the land.