So, what’s the deal with Frost Lich Janna you ask? Why is she so powerful? Her power comes from her new hero power, called Icy Touch. This is a 9-mana card that gives you 5 armor, summons one Water Elemental, gives you a brand new hero power, and it makes all of your Elementals have Lifesteal.
The biggest offender is the Mage class and its Hero Card, Frost Lich Janna. Granted, if you are in a winning position, and your opponent is really behind, then you’re probably going to win even if your opponent plays a Hero Card, but in the case where you’re both in the late-game and the board is even, playing a Hero Card is going to swing the odds in your favor in a huge way. If you go against a player that has a Hero Card, chances are that you’re going to lose no matter how good your deck is. The problem with these cards in Hearthstone’s Arena Mode is that they are basically a must-pick once you see them.
They basically act the same way as Lord Jaraxxus, as they replace your hero with a Death Knight that has a brand new hero power and an active effect. The latest Hearthstone expansion, Knights of the Frozen Throne, introduced a brand new type of card, the Hero Cards.