I just noticed that Aquazoid has returned to the website (maybe it has been there for a while as I haven't checked since late last summer). I take that as confirmation that the ride will be repaired and reopened by next season, and I'm happy about that.
Hence the expense portion of why not - but I see that many of the newer rides use steel and concrete so it could have been due to cost at the time and aesthetics?Weight?
The heavier the the platform, the more reinforcement it needs. The more reinforcement it gets also makes it heavier.
I imagine it is a massive expense to make a platform as you describe.