Why would Valve want to solve that problem (which is certainly not 'easy to solve'. It's possible to solve it but it's certainly not 'easy' and it also would result in needing a bigger/better server since you need to check all other bug reports and not only by using the exact text but you need to throw words around and search the entire database multiple times. And even a company like Valve isn't going to buy a high-end server if a virtualized server will do the job just as good) if they don't need to?
In that stage of the beta phase they want to fix obvious bugs. It doesn't matter if you've 100, 1000 or 10000 people looking at the program. They all find the same bugs.
@Naib you should probably try Heroes of Newerth.