While I support the principle behind this rule (making sure the wealthy pay their "fair share", whatever that means) it's probably a bit of a kludge solution. The real problem is that the tax code is so complex and with so many giveaways to special interests. This is not just in the form of tax deducations or shelters, but in actual government handouts.
I think there's a growing perception that the game is rigged in favor of the wealthy, and I am inclined to agree with that. This sort of rule acknowledges that and so acts as a blanket protection for all of the individual shenanigans that go on on the tax side at least.