Couple of years ago I was into that shyt hardcore. Hyped from the beta and was my most played game for months after release. Dropped it due to:
1. "ladder anxiety"
. If you can't handle stress well you might want to keep to the other modes--I've heard they added some type of dungeon run thing recently.
2. Expensive. If you want to stay relevant and adapt to the ever evolving "meta". Unless you have been grinding since day one or like grinding Arena period you probably going to have to spend some money on packs and getting into Hearthstone at this point is pricey for a newbie.
3. Stupid over-the-top RNG bullshyt cards. The devs have said they like the randomness of the game, but they went too far in embracing it.
4. Often times a shytty community has formed around it like a lot of modern Blizzard games.
I stopped playing right after Goblins & Gnomes (think that is what it was) expansion back in late 2014. Saw the "writing on the wall" back then of where the game was headed. Game was fun for about a year when I was checking for it heavy, but I have vowed never to touch it again. Only card game I'm playing is Slay The Spire (a PVE, rogue-like, deck builder game).