To put it simply they are trying to regulate the amount of gold you can make by reducing the amount made on a daily basis while spreading that amount over time, all while motivating their players to play for a longer duration and on a daily basis. It is a natural occurrence of Activision Blizzard and to be quite honest it has been a long time coming. I am actually amazed it lasted for so long but finally they are showing their teeth.
Ask yourself this, why would a company completely revamp a system that was working just fine and was particularly good for casual F2P players? If it ain't broken why fix it?
Their tavern passes and their battlegrounds (and their duels soon) were not very appealing to me. I didn't find a need or a reason to buy that terribly priced tavern pass and probably a lot of others as well. They wanted to have players buy it and not ignore it like I did so they created this system(to manufacture a need for it) that gives "XP" instead of gold so you can get stuff that they picked for you in their "XP progress trail". They removed your ability to choose how you use your in-game currency and at which speed you accumulate it while making you argue with each other on whether this new system is better than the old.
If you ask me they are doing great as a company. This new system though is much worse in many aspects that go by the average math enthusiast.
Whether you continue to invest time or money in this game is entirely up to you.