A very simple approach would be that for each count that the defense can strike off as irrelevant or spurious, they would also get to strike off any other charge of their choosing. That alone would make prosecutors extremely wary of bringing up random charges in hopes of seeing which they can make stick. They would need to have solid evidence for each charge or risk having the most serious ones nullified.
On the other hand, I'm not naive enough. The cure could well be worse than the poison it was meant to address.