The maximum length of an IRB-approved international rugby ground is 100 metres from goal-line to goal-line plus 2 x 22 metres for the in-goal areas, a total of 144 metres. Very few rugby grounds are actually this big but Murrayfield, Twickenham, Lansdowne Road and the Millenium Stadium are not far away.
By contrast, here are the lengths of the afore-mentioned football pitches:
Old Trafford 106m
The Emirates 104m
St James 101m
Given that the minimum size of an in-goal area is 10 metres, and the 22 metres between goal line and 22 metre line is sacrosanct, the size of the playing surface between 22 metre lines has to be reduced in the above cases to between 42 and 37 metres, compared with the 56 metres expected at an international rugby ground.
Thus the rugby play becomes cramped and the aesthetics of the game are diminished. That this should happen in the showcase of international rugby seems disappointing.