I suppose because there's already two small covered terraces and a small covered seating bit on the side opposite the main stand, it made more financial sense to put new stands in where there aren't any already - ie. behind both goals.
I'm a "four or five games per season when the Dons don't have a home match" attendee and I probably slightly prefer standing along the side of the pitch - my season ticket at Pittodrie is behind the goal. What's most important is being able to see the game though, and what puts me off - despite being tall - is the prospect of standing in the "second row" when there's a decent crowd at Balmoral. I really can't be ersed turning up 15 minutes before kick off to get a spot at the front, so I was hoping for some additional facilities to get built. I have no idea if I'm representative or not but I'm happy with this news!