We can fix this problem and get patent reform at the same time.
After 3 years, patents issued to foreign based or owned companies can't be enforced against US owned companies making products in the US that utilize them. Patents issued to American owned companies using the patent to make a product in the US can enforce them for the normal time against anyone.
This solves the problem with obnoxious multi-nationals hoarding patents by making them only useful for a very short time. It discourages US companies from "inverting" for tax purposes but largely remaining American corporations (and thus benefitting from taxpayer provided legal, diplomatic and protection but skipping out on the taxes). And it encourages businesses to make products in the US.
Of course companies with insanely good and hard to make products may choose not to sell them here because of this, but the upside is there'd be an incentive and means to make them here by other means and for the most part, willfully refusing to sell in the American marketplace is like throwing money away.
There's no reason that the patent system couldn't be used as a tool to encourage business in America and discourage evading paying for the very civil society that makes business work. Hopefully now Pfizer will be utilizing the vast resources, long reach and deep influence of the Irish government to enforce their patents, lobby governments when they don't get the treatment they want, when, say a new drug is copied in China or India or when the FDA doesn't approve it.