Those aluminum castings are not unique to the Wave, they've been used on just about every Hobie made since the mid '80s...the 17, 18, 20, 21, Tiger, and Wave. They're a very proven design. But if you hit bottom with your rudder while going backwards on a wave, it's very likely that you're either going to break some part of the rudder system or tear out the back of the boat.
I don't know if it's possible to do this on a wave, but maybe you can switch to nylon or aluminum rudder pins. This way if something happens, you break the rudder pin rather than a more expensive part of the boat. Also, don't lock down your rudders until you're sure you're in deep water and have enough speed that you won't get knocked backwards.