The patent system needs a reward for people who prove that a patent is covered by prior art or by other patents. Clearly, the USPTO cannot be relied upon to do this job, so what's needed is an incentive and a mechanism whereby a bunch of freelancers can do the job. It would also serve as a disincentive for companies to apply for bad patents, because they'd be the ones stuck paying the reward.
Then, you can get rid of the patent examiners working for the USPTO, cutting costs and streamlining the whole system. The good ones can work as freelancers, either employed by companies to make sure their patent won't be invalidated, or as the ones invalidating the patents like I mentioned above.
And the bad patent examiners? They should find another line of work, anyhow. The sooner, the better.