Believe it has been about doubled from its original values in the Spring update.Muldar, how much has the purple tokens drop rate improved? It took me 27 days of doing 12 bounties each of those 27 days (6 each on 2 toons) to get 1 purple token. I (and I'm sure I'm not alone) don't do bounties for the xp. I strictly did them for purple tokens and unless the purple tokens drop rate has been increased exponentially then the time invested in doing bounties for a pet is not worth it.
Of course there will still be cases where people don't get due to chance but it has at least been improved which should hopefully help.