I don't think the Falmer platforms ARE being extended, although I await correction on that point.
And two factors about the Goldstone: firstly because of its 'in-town' location it was in walking distance for a LOT more people than Falmer will be. Secondly there was a lot of on-street parking available; if we drove over from Lancing we never had a problem parking. Both those two methods of transportation, for different reasons, will be severely curtailed at Falmer.
I hope you're right though about the 'unecessary panic', but on the other hand I think we're right to be concerned about it. At first glance it does seem as if it could be a problem.
I seem to remember Lord B saying that there would be work on Falmer Station to allow longer trains but I may have got that wrong.
My memory of Goldstone is that it was a bit of a pig parking. I remember going with father once by car and having to park the other side of Hove Park - we never tried it again. Maybe you just had to get there early. Don't forget that the stadium will have car parking at the uni - the Goldstone didn't have a dedicated parking area.
My guess about the logistics is that this was a plan that was pored over by countless experts, went through two enquiries, with opponents looking to pounce on any flaws and got passed by an inspector and a government department. The figures must have added up for them.
Still, what do I care? It's a five minute cycle ride or a 25 minute walk for me.