Vredenburg is still standing, and will stay there. Another building will be built on top of it. Information on that design can be found here: [
www.hertzberger.nl]
Choose -cultural spaces- from the menu, you can find the Vredenburg design using the strip at the top of the page.
And for the architecture: it is indeed a lot of gray brick, more gray brick and off course some more. But that's just the way they built in the seventies. No nonsense, every guilder is put there, where it is most needed. Typical Dutch. Lack of historical value? Maybe, could be and probably. But technically, from the accoustic point of view, the building is excellent. Like I said: built for music, and for music only. In Ahoy, which is more like a huge metal candy-drum, they have to work SO hard to get an acceptable sound. Nowadays they have it pretty much worked out, but I think that Ahoy's value is more in its cultural importance, all the great musicians have played there. But hey, it is the ONLY 12/15000 seet venue in the Netherlands...
And now I really have to get my nose back in my books, otherwise I'll never finish my study architecture... ;-)