After a stressful day of grinding out ranks in Ranked mode, sometimes players just want to relax and dive into Arena as they generate their random deck. But the worst thing about this mode is generating useless cards and being forced to draft them. Well, Blizzard has decided to balance out Arena by removing a decent amount of those terrible cards.
About 3 weeks ago, Blizzard removed Purify from Arena and it is great to see that they decided to continue balancing out the mode even more. Many agree to this upcoming change as most of these removed cards need an entire deck based around them to make a remotely successful deck, so drafting any of these cards can only worsen the deck. So pretty much, this change is focused on making Arena more competitive than it already is by drafting good decks easier and strengthening weaker classes.
For example, Mage is the most dominant class in Arena and the class is going to be more balanced out due to the removal of two very strong cards: Faceless Manipulator and Forgotten Torch. These cards are also common cards, which explains why it was so easy to build a great mage deck.