Thanks for all the feedback and bug reports! I have made some big changes with the Kill Rankings that will be updated soon (just after the capture is done).
I have also given the app I wrote to generate the listings a major facelift by adding a SQL database. This will make it easier to do more with the listings and play with the data to see what metrics are viable. In short, I will never post a list with 22 hunters in the top 25 ever again!
The new Kill Rankings metric is based off the following formula:
Kill Score = (Killing Blows + Honorable Kills) / (Deaths + AFK Penalty)
Minimum Criteria: 2000+ combined HKs in WSG and AB.
The reason I chose to add HKs is so that healers could fairly be represented on the listing. Healers will generally have fewer deaths and killing blows.
The AFK Penalty was added to counter the bias that AFKs have on the statistics.
AFK Penalty = 2 * Estimated AFKs
In order to estimate AFKs, I first calculate the average number of HKs per battle (e.g. WSG: 44.368 AB: 37.578)
I then compare each players average with the overall average to estimate number of AFKs:
Estimated AFKs = (PlayerAvg / OverallAvg - 1) * Total Battles
For example if the overall average was 40 hks/battle.. and your average was 60 hks/battle and you played 100 games (according to armory), then you would have 50 estimated AFKs.
The AFK penalty is determined separately for WSG and AB, the numbers are then added together, and only applicable when the combined value is positive.
I'm sure this formula will be up to much scrutiny, but it was the best I could come up with after hours of playing with the numbers. Please if you have some criticism offer a suggestion on how it could be improved. I think the end result is a diverse list of well-respected players on top, and will let you decide that for yourself.
I am still planning a PvE rankings, and the refactor of app was paving the way for this to happen. I was planning a metric based on PvE statistics including professions, reputation, etc. The problem I see with a "pure F2P" achievement list as suggested is that even if you are "pure F2P", the achievements are shared among all characters on your F2P account, so you could roll a new toon and start with all your achieves. Also, there is also no way to know for certain if a toon is pure F2p (i.e. it's possible you have a P2P and didn't level it past 59).