My criteria is overall skill on 1v1 2v2 and 3v3s... To be in the top you need to be flexible on all formats. It's mainly about what you've achieved in the past and roughly where you are now, They are both factors in my top 30. All players are still playing in some form which counts as active.
Hard to take that list seriously if you don't include me with those criteria. (Did you check the 1v1, 2v2, 3v3 and seasonal ladders somewhere in the last half year for example?).
(Although not including me would take sense if you used other criteria.)
As an on-topic reply: pretty much impossible. Top 30 is so wide and very subjective, there's probably already 30 people you could consider for a top 10. If you would ask all somewhat good strategic players (say top 100 in 1v1 or something similar (like top 15 in 2v2, top 50 in a seasonal, ...)) to give you a top 10 of the players that they thing are the best, you'd probably end up with more than 100 names.