Just a FYI, nobody outside of the HTC company has the ability nor knowledge to make such a claim...
Going off the status of how many kills have been recorded through out the years just from the main malee arenas , you're discounting the AvsA, TA, DA, SEA's and all the different special events as well as scenarios and also the players/groups who likes to utilize the Custom Arenas area of the game....
I'm not saying number of players have stayed the same, increased or dropped....
I am just saying its not correct to answer with a blanket statement that number of players are down 50% over the past two years...just going off of tour kill totals...
One should also take into account the fact that numerous players have been helping with the new AH Alpha as well...
Hope this helps
TC