I wish these sorts of suggestions were less on the end of "here's what would be better" and more on the end of "here's how it would be possible". Anything that requires a magic wand to enact is a bit of a waste of energy. Would love to see more actual action plans on how to enact the change though.
As stated in other comments, it would be actually easy to implement as it doesn't require a change in the constitution.
Anyway, as I told in another comment, I'm not from the US, so my intention wasn't really to say how to implement the proposal. I just had this idea and wrote it down in a blog post.
Yours is a very good point of view actually. I initially hadn't thought about the tragedy of the commons situation where all the states agree to implement it and later one state decides to go back to winner take all system.
Ok yes maybe "easy" isn't exactly the correct term, but the way to appoint electors in each state doesn't need a 2/3 majority in every house + 3/4 of the states as it happens with Constitutional amendaments. So it's definitely an easier approach