I don't think there's any over optimism built in to this. Any attempt to tax an almost $20 trillion market is going to be complex. I find it hard to imagine tha

I don't think there's any over optimism built in to this. Any attempt to tax an almost $20 trillion market is going to be complex. I find it hard to imagine that it would be any more complex than the current scheme. And on that point, that's all it really needs to be: not worse. The real benefits are in other areas.