The only datamining I'm aware of is datamining Xûr, whose inventory is likely random but rolled several weeks in advance. When you hear about people getting an absurd amount of something or not getting a specific thing after hundreds of attempts, it's actually biased data. Those people are statistical abberations, outliers if you will, but only the abberations feel the need to post about something, so to someone who bases their ideas of the games RNG based on what they read on the forums it will seem different than it likely is.