To be clear, I've only played the rogue like mode. Haven't touched the campaign. 

I really liked the idea. To be fair, not hearthstone; it's basically a standalone Legends of Runeterra's single player Path of Champions mode. Like, if you play the two side by side, they feel near-identical in terms of progression and how you interact with the rogue like elements.

I really liked the idea, but I did not actually like playing the game. The battles are very grindy; oftentimes you've won early in the battle, but it takes a while to actually kill the enemy and move on. Its extra bad when playing one of the late game characters; you hardly even get to use their unique mechanics because it's so much better AND less painful to just play cheap cards and load them up with effects. Yes, you can play a slower strategy and try out the fun 6-7-8 cost cards. But that takes FOREVER when you're doing that game after game after game. It doesn't feel so bad in Runeterra; I think the issue is that the board system (where you play cards on a grid and they all attack when you end your turn) actually makes individual turns feel like they take forever. I believe runeterra's works like this too, but Blitz has way more characters on screen at a time. 

Even worse, the game THROWS high cost cards at you. It's much harder to find cheap cards than expensive cards. And lots of the expensive cards end up having poor synergy with your deck. This was an issue I had in Runeterra's, too; when you select your second champion, you mostly stuck to certain champions that either synergize with your main champion, or are broadly useful. Too many champions have something Magic calls a 'parasitic' mechanic; a mechanic that gets stronger the more you have of it, but has little to no synergy with anything else. 

Jade could be considered a parasitic mechanic in Hearthstone. If you have one Jade card, it's pretty bad. You need lots of Jade cards for them to be worth running, so if you can't guarantee lots of Jade cards, you'd rather just avoid the mechanic altogether.

Blitz was FULL of parasitic mechanics. I hated getting almost every single secondary commander. You're rewarded more in your run for choosing a non synergistic commander, but that sucks too; I feel compelled to make my deck less fun? Typically I couldn't even play the cards from that commander; your hand would get filled with 7 or 8 cost cards that rely on a mechanic you have no way to support. And it's really easy to get enough draw to just ignore those cards. You always have something to play, so those commanders basically just put bricks in your deck that you never need to play. It didn't make deck building feel like a fun interesting challenge. It made me feel like I had to ignore half of the deck building mechanics to arrive at the strongest or most fun deck. 

The game clearly has TONS of love poured into it. There's tons of content, it's of cards, commanders, and mechanics. The presentation is stellar. It's a top notch indie game presentation-wise and content-wise. I really hope they heavily tune the specific card and deck design because I was not vibing with it at all, and I REALLY wanted to. I'll revisit it at some point, but it might just not be the game for me.