For the most part I agree with this list. Portugal are already making very favourable noises. Greece I'm less sure about.
But I will add that some Western European countries that are very difficult to get a visa for longer stays -- France, Italy especially -- if they haven't made exceptions for US visitors, where the numbers are slightly higher and the spend likewise, they may not make any for the UK.
I suppose the proximity argument might factor in if e.g. a holiday home means much higher spend.