No agenda whatsoever, i simply agreed with several others that the North stand is a bit of a non-event, (have they all got agendas too......?) with the roof so high above offering little or no acoustic enhancement.... it is essentially an open air end for most fans seated there. The full height corners will help with that of course.
I suggest you look again at the Principality Stadium. The middle tier overlaps the bottom tier for almost its entire depth. I've been there many times (work and pleasure) and sat in every tier surveying it. It's deafening with the roof closed, but still very loud with it open, because of its proportions with the large upper tier directly under a deep roof.
Yes, there is some noise entrapment.... at the back of lower Gwladys St, ive mentioned it many times, but it is also a real din under there, and where many of the chants actually propogate from. That area is contributing and was always the place were chants started because of that low roof. Similar for the away fans occupying the Bullens Rd. Nowhere have I said its ideal....