I think the Guild League system is kind of stale and not very fun. The top guilds haven’t changed in months, and the gaps are so large that I doubt they will any time soon. I’m in Vn4Ever, ranked #3 (for months), so this isn’t simply about wanting “my” guild high on the list.
I think starting over on a monthly basis would make the League more immediate and exciting and fun, especially if it’s done in preparation for guild wars, etc. It would also allow other Guilds to have a realistic chance at hitting #1, even if only once or once in a while.
Of course, it would be good to have Stats that can record achievements, like “Average Ranking” and “# of Months at #1” or something, so that all previous achievement isn’t simply lost, either.