I don't think they would consider closing hex. It is in a very unique location, very few, if not no other rides could fill the space as the majority of the ride is inside the actual towers, with only the vault that isn't the original building. The application for hex back in 1999 stated that if hex was to be closed, the fact that it is connected to a grade II listed building would mean that all traces of the ride would have to be removed. I think that if the queues became too short, instead of closing the it, they would shorten the pre ride videos as it may put some people off re-riding. That said though, i always notice new things every time i go on hex, small details i didn't see the last time. My visit isn't complete without hex. I would say it is possibly my favourite dark ride and has the best (even if not completely original) storyline it any AT ride