You're right about patent trolls, but this would allow those companies to have access to a vast amount of patents, so it should become harder for patent trolls to sue any of them, although far from impossible.

But the patent pool would be mostly so those companies don't sue each other. So many companies in the tech industry are suing each other right now. It's ridiculous.

Having access to a large patent pool provides zero protection against NPEs ("patent trolls").