The structures of systems have always fascinated me, so I'd like to break down how the new system is designed to influence players and get them to spend more money.
1. New XP System Obfuscates How Much You're Actually Getting
Before, you got 10 gold per 3 wins. You got 50-60 gold per quest. It was easy to understand and if anything changed, you would know immediately.
Now, unless you're really into excel spreadsheets or read reddit regularly, you can't exactly tell how much you're getting. In fact, how much 1000 XP is worth varies depending on how far into the pass you are (it mostly drops later). This opens the door for Blizzard to do several things:
A. Frontload the Rewards - Pretty much everyone noticed how incredibly you level at the beginning. I am already level 20, and it feels great! It's no coincidence that this part of the pass lines up with the release of the new expansion. The euphoria of getting so much free stuff so quickly will convince many unaware players to spend more during the most critical part of the expansion cycle: the release. Once rewards taper off and people start getting upset, they've already spent the money.
B. Reduce how much they're giving out - In future special events, they'll probably just give xp boosts/flat xp. Players once again don't know if they're getting less because it's not as simple as 60 gold -> only 50 gold now. In fact, people who don't play often will actually think they're getting more (frontloaded system). Also, the later 200+ gold bags seem amazing at first, but that is only until you realize it'll take many more times the effort to reach.
C. Sneakily replace actual rewards with less valuable rewards (like older expansion packs).
D. Sneakily insert rewards as part of the pass that people used to get for free. On expansion day, you used to get a bunch of free packs and a free legendary. Now, it's all part of the battle pass.
E. Sneakily hide the XP progress bar after each game UNLESS you completed a quest - It's not obvious immediately how hard you're getting shafted by the pithy XP rewards per game.
2. New XP System Introduces Non-Continuous Rewards
Before, if you needed 10 or 20 gold for a pack or arena run, you could just grind it out. You got daily gold through quests. Basically, if you needed something, it was always within reach.
Now, though, you are frequently "stuck". You need gold, but the next level is so far away. Sometimes, there are useless packs and other rewards in the way. You may need to grind for weeks to get that next bag of gold. And once you get all that nice juicy gold, you're tempted to spend it all immediately. Then you're stuck again.
All of this incentivizes you to spend actual money since you can no longer get your daily fix.
3. New passes and bundles give you less and include things that you used to get for free
Remember when battleground perks were kind of free? At the beginning, all you had to do to unlock it was buy 20 packs. Now, you have to pay 2000 gold and get no packs.
New tavern pass is filled with cosmetics. The only value-giving part of it is the XP boost, which seems nice until you realize the sum total is still less than what you got in the old system. It's also terrible that the mega-bundle doesn't include these rewards.
4. New Expansion Format Makes The Game More Expensive
More cards + mini-expansion = more packs needed to get what you want.
Whenever new cards come out, people need to buy packs to stay competitive in ranked. Blizzard can quite conveniently cloak all of this as "we're just giving you more updates and more cards!"
In reality, it just costs more. The mini-expansion is a shameless cash grab for anyone with half a brain.
Conclusion
All of this is very concerning, not just because Blizzard is taking advantage of us. The most concerning part is the DEGREE to which they are doing this. Any one of these design decisions could be very profitable and bad for the player by itself.
But all of them at once? This is looking to me like some sort of final cash squeeze before devs just give up on the game completely and maintain it with just a skeleton crew in the future. It would make some sort of sense since rumors are that the game has been hemorrhaging players and revenue recently. It's just sad that the company is deciding to do stuff like this instead of trying to revitalize the game with more and better content.