Yeap, the main hurdle which will make it completely unfeasible is that cost of it will likely to be £50m+ which for another 8k-9k seats makes no commercial sense unless we jack ticket prices up and demand outstrips supply.
The latest Etihad expansion had a cost of about £50m for about 7k new seats, the club mentioned that it would take almost ten years to recover the money but after that it was all profit. It did of course mean that there was extra space for corporate hospitality though..
There's no guarantee we would be able to sell another 8 to 9 thousand extra seats.
If we get substantial investment, shifting season tickets won't be a problem. Remember the waiting list when SBR was manager? 52k inside the ground with 10000 on a waiting list, IIRC.