Expanding on your second idea, there is a distribution of votes by level for a given day. Articles that were close to the distribution keep the points, other articles only get the fraction of the points that meet the distribution. This means you 'throw out' the extra level 2 voters, in essence.

So if 20% of the daily votes are given by saints, and a post only has 10% of the votes delivered by saints, then we throw out lower level votes until the saint's portion is 20%.

To prevent the saints and higher levels from being the gatekeepers of XP, there would be a wiggle factor, so in the above example you would only throw out lower votes down to say %15 saint.

-jackdied