Doesn't the UK have different laws than mainland Europe in regard that stands cannot go past a certain degree for steepness,looking at the Yellow wall at Dortmund that stand is so steep but no modern ground/stands in England have any stands that steep.
Hence why all these modern stadia here all have the same design especially the bowl shaped ones,Allianz arena is bowl shaped but looking at it those stands seem alot steeper than say the Emirates,stadium of light etc,also Spurs are doing a single seater behind one of the goals in their new stadium and i'm betting it wont be as steep and high as Dortmunds due to the regulations we have here.