"Better to try and fail than to never try at all." That might not be a universal truth, depending on the cost of failing, but in the case of submitting voice files it certainly applys I think.
The worst thing you can lose is a bit of time and bandwidth. And even if you don't get selected you still might learn something.
That was certainly the case for me, since I learned a few things both from the experience and from the feedback I got from the people who managed the VAing effort (in particular Rian, General Battuta and IssMneur).
Also considering there are much more roles in WiH than there were in AoA, I'd guess the chances of getting cast in WiH might be better than they were for AoA.