There is MASSIVE problems with it's current implimentation that completely throw out most enjoyment that could be gotten.

1st: "Failure is punished".

It's a single player mode. Why do you punish people for rerolling? Hell, for failing. Especially with how absurd the AI cheats get from 3 stars and up.

Yet when you die, you basically lose your first level power AND have to defeat two enemies? That's... just anti-fun and even worse, a time waster. I understand you don't want people to reroll to get better powers. But have you considered... for one, it's a solo experience. (They don't care, because players getting through it quicker means less chance to monetize) and two, just use a better solution like locking the powers and not allowing rerolls between the same champions on the same map. STILL better than saying "Here is a literally worthless power, enjoy beating two enemies to THEN reset". But nothing annoys a player, like feeling a game doesn't respect their time.

2nd: Variety doesn't exist.

No, making some "event nodes" does not count as variety. What the hell is the point of the path of champions? Is it just a kind of "eh" campaign? Why is there no RNG dungeons so you at least have A REASON to do your daily quests and level your heroes. I am so tired of doing the same stupid runs over and over.

Together with the next point of how poorly challenge is handled, this makes all runs feel like slogs that exist to wear you down and exhaust you, make you dread bad powers as you know you'll get punished for it.

All that while fighting stat stick opponents. I guess in a way it really is closer to the league of legends experience than I had expected.

3rd: Challenge

Challenge is done pretty poorly, a lot of powers are not interesting. That's what the dungeon runs in hearthstone did well. A LOT of bosses were a blast to fight and more held back by blizzard not caring about modes they can't make people pay for.

But these bosses riot have just kinda suck as it feels like they plainly exist to check if your deck is op and your hero is leveled up high. Most powers are plain super insane mana cheats and it's not rare to take up to 15 damage on turn one with the enemy having a full board, before you even reach 3 mana. Unique powers are beyond rare as most are just (deal 1 damage to the nexus every x) or (gain 1/ 1 whenever an ally dies) or (strike an enemy at the end of each turn), or if we're getting spicy (generate a 4 cost card, it costs 1 this turn). Always that stuff.

4th:

Monetization

If you want to monetize it, do it. As of now progression feels pretty bad and I'm saying that as someone who's played quite far, because I love the idea.

But why keep it in this limbo where nothing happens until people run out of interest in the mode, just to eventually patch it in when most people don't even play anymore?

EVEN moreso. If you can buy shards or the like, then what's the point? There are no random dungeons. As of now progression is THE entire thing, and while it's already pretty poorly balanced, what the heck happens if I go in with my 3 star jhin from minute 1?

As an end note:

Don't get me wrong. I don't hate this. I think it could be the whole hearthstone dungeon crawl done right... if they adress these problems. But right now it's kind of a massive grindy mess that feels like it doesn't have any clear direction and that is in a limbo between setting up for microtransactions and being utterly unsuited for it. And I feel that's just about THE worst place to be. Because I'd be surprised if it's not losing them people who are interested in it, while ALSO not actually generating revenue.