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..