@Craig *******
I find your arguments valid and I appreciate your post. I agree it's risky and it's not advised in most situations. I don't think it's as risky as you mentioned but I agree that it can cause serious complications if not done properly. You need to be well aware of the risks and fully trust the person you are doing it with. I also wouldn't do it with a woman that's not at least your equal financially, as you mention its that part that could potentially give the most trouble. I also would simply file a divorce, thats been agreed upon from the start, if you don't need the visa any longer or actually considering to remarry. All this should be agreed on with both parties.
It would be great if you do it with someone you actually care about a lot so it isn't hard to provide any proof requested, especially at the beginning.
If all those marks are checked, I don't see why it isn't a great option in case you plan on staying long term. You just make use of the options available.