I first have to declare that I reside in the UK and so, I believe, am ineligible for the draw.
As regards principle, I should have thought that, given the spirit of this 'site, it would be perfectly acceptable to change the rules in light of the experience of those rules now available.
I doubt any reasonable person would object to a manifestly fair draw, involving only single entries and, (though this might be a step too far), an entry qualification (length of membership, number of posts etc.).
I readily concede that the practice of making any such amendment might have to be filed under "too late, too difficult".
Regards