Well, I never said you are wrong. I did not put a lot of time to count XP in excel, so you might be right. I am just dumb mechanical engineer so I am kinda pragmatic.
What I see is that in actuall reward system I am not gona get the same amount of gold as from previous case. In addition I am forced to play new expansion, arena (for exmaple win 4+ games in arena) and others, which costs me gold. So Blizzards forces me to spend gold to get XP to get gold. From my point of view it is not worthy in the end. They just force players to spend more real money and time in HS.