Notice how it is completely unrecognisable, but still the famous walls are left, seems really weird how there isn't even a pitch anymore

what are they putting their instead

Flats, although I thought they were going to be built in the positions of the stands (and of course, in the listed buildings), then have a courtyard where the pitch was. Still, its not Highbury anymore, its just a wall - whats the point in listing a wall if you don't list what it was a part of?