There are limits on the rake of any new stand - meaning the steepness of the top balcony can never be recreated in a modern stadium
There are also rules on how close to the pitch any new stands can be
Max is 34 degrees, Top Balcony 37. For a large stand the gradient can increase about 5 times say about every 15-20 rows due to sightlines.
If a large stand starts off too steep then it will hit it's maximum gradient too soon. The closer the higher tier the steeper it must be to make those sightlines, generally meaning the shallower the lowest tier must be.