Any expansion/new build must look to the future. If a 32k ground is feasible now, what would be feasible in 20 years? The M25 was a failure of planning, the traffic volume of the future was either not factored in, or totally mis-calculated. If we fail to correctly define future needs we will be having this discussion again in 20 years.
Then there's always the problem of 'underpopulation' (in the extreme!). ITFC developed the Portaloo to hold over 30,000 when times were good.....which they haven't been for decades. Nothing worse than the library atmosphere of a less than half-full stadium. Optimism of a prolonged stay in the top flight is fine - but hey, we're NCFC, let's be 'avin' some realism!
The people best placed to judge whether stadium expansion is warranted are those who manage ticket applications at Carrow Road. You don't react to a surge in demand resulting from short term success; you react to consistent and inexorably increasing demand season after season. Given that, only two seasons ago, demand for season tickets was falling and a previously steady waiting list had all but been eliminated, I don't myself think anyone could say that a significant expansion of capacity is currently a priority. Didn't Ben Kensell say as much in a recent interview, while also making it clear that it's a question which the club has constantly in mind?
Some excellent points being raised and as Robbie says, now is NOT the time to be talking about ground expansion – the club were able to offer ‘half-season' tickets last season (which were rapidly snapped up!!!)
I remember when this was being discussed, 2012 I think it was, David McNally said that increasing capacity to the envisaged maximum would cost 20M and raising and servicing that level of capital expenditure would seriously impact the funds available for transfers and wages. He doubted whether supporters would really want that. It's no different today: expansion comes at a cost (ask Arsenal fans).