There was fail when I tried posting this to there ---->
http://www.antipope.org/charlie/blog-static/2015/08/how-i-learned-to-stop-worrying.html JC - I know you've left the building, but for anyone else considering that requiring semi-regular attendance at Worldcons before a member can nominate or vote etc. I'd like to reply from my own experience.
I live in the UK. I have made it to two US cons in my entire life (my only trips to the US). Only one of those was a Worldcon. I have, however, bought a supporting membership simply to vote.
For a US fan to attend a Worldcon once every five years would be inconvenient and a bit expensive (ruling out at least one section of the annoying people that Pup... no I can't say puppies, puppies are cute and like me, SPs and RPs are not as cute as puppies) but for Non-US fans? Worldcon tours, but even when it comes to the UK it tends to be a bit pricey to attend and even then because the location is decided by vote there's no certainty it will be close enough to the majority of international SFF fans for them to go enough to qualify under your proposed rules.
In my own case, I have chronic illness problems, and both times I went to the US I was ill when I got on the plane home, and had a full blown chest infection by the time I got off the other end. As I've said to friends - I probably won't be going again unless I've transformed into a writer, with panels and readings and stuff, rather than as a fan.
Not everyone who wants to feel part of the process can attend let alone attend regularly. While the problem is magnified if you live on another continent, I'm fairly certain there are US citizens who would also suffer for your rule change and so oppose it rabidly.
There is an easy and peaceful answer, though...
"This gets back to the core disagreement of whether the Hugos are an award given out by a small Worldcon Community or any and all of SF/Fantasy fandom who care to vote."
Here's the thing, if you disagree with the fact that the Hugos are what they have always been - awards given out by the small core of fans who attend and support Worldcon - go start an award that can be voted on by "any and all of SF/Fantasy fandom who care to vote" (although don't the Locus awards do that?) Instead of wasting all that money buying supporting memberships to game an established award use it to promote your own. Have a kickstarter. If you create your own award you can, as with the Nortons, the Dicks, the Triptree etc, make your own rules about voting and what qualifies. Have your own categories and your own traditions and trophies (and be prepared to smile bravely when whoever cares to vote ends up voting for the same things that win Hugos or for a paranormal romance)
If a cross-head screwdriver isn't fit for purpose you don't spend time and money buying a file and scraping away the offending metal so as to make a flat-head - you go buy another screwdriver.
Why piss in the Hugos paddling pool when you can have a pool entirely of... writers whose fans are not the kind of people who normal give money to Worldcons?
And it didn't vanish - it stalled and then got repeated... *facepalm* It kept telling me not to try and post it...