I can assure you Blizzard hires nothing but the best.

Lol.

Though smaller than any other team at Blizzard — it started with 15 people and grew to a mere 30 — Team 5 included a mix of long-time veterans of the company and new blood brought in specifically to help them create a type of game the developer had never done before: a card collecting game. Once more, Morhaime and Metzen point to their long nights playing Magic: The Gatheringas an inspiration. Morhaime calls the long-running card game "brilliantly designed."

Source: http://www.polygon.com/features/2014/10/3/6901193/blizzard-entertainment-three-lives

Want to guess how much of that “new blood” was the programming team?

Hearthstone's programming team is smaller than any other Blizzard project. The game is impressive considering how few people worked on it but compared to other Blizzard products it is severely underdeveloped which is why it lacks so many basic features of other MMO games such as Dota 2 and LoL like first-party stats collection, reordering your decks, lobbies, guilds, a halfway decent chat system, more gameplay options e.g. for colorblind people (buffs and damage are green/red), and replays.

The truth is that Blizzard has always put Hearthstone on the back of their priority list, ever since the inception of the project:

"Honestly, selling the game [Hearthstone] internally was one of our biggest challenges," Chayes says. "It felt very different to a lot of the people here. And rightly so! It just feels different. That evangelizing effort was always a big challenge for us."

In the end, Chayes says the Hearthstone team never discovered the perfect way to convince people of Hearthstone’s values with words alone — it wasn’t until people from around Blizzard started actually playing early versions of the game that they came around. Chayes describes a process where Blizzard rolls out playable versions of games in development to people across the company layer by layer — first the dev team working on the game itself, then other development teams, then the wider company as a whole.

And then in an interview from a few months ago one of the designers confesses that they take a "design for now" approach to development.

It's pretty obvious the team is not doing things perfectly. That's probably due for budgetary and time constraints as it's clear that Blizzard didn't take Hearthstone very seriously when the game was being initially developed. And those things add up over time.