There has been a flurry of new cards revealed in the past few days. This article covers four of them, which are: The Boogeymonster, Xaril Poisoned Mind, Infest, and Renounce Darkness. This brings the total number of revealed cards to thirty one.
Although we don't have anything like complete information, this seems like a weak constructed card. The extra two mana paid over the cost of seems to make the upside not worth it. The clause about having to attack even removes any fun that could be had by giving it taunt.
Xaril is a fascinating card, and is in a class that can make good use of the cheap spells it provides. The Toxin cards are pictured below.
It seems likely that Xaril will see play in Standard. Although the stat line is bad, the Toxin cards seem powerful in Rogue. As well as being activators for Combo they also work well with cards like which is played in Miracle variants. The Deathrattle has some synergy with , and it will be interesting to see exactly what Xaril's role turns out to be.
Infest is another piece on the way to a Control Hunter deck. It doesn't seem likely at this time that it will be powerful enough to push that deck to the fore. It will likely see testing in Midrange Hunter to see if it creates enough cards often enough to be of use.
Writing a sensible paragraph about this card without having played it is a difficult task. The upside of cards costing 1 less for an entire game probably shouldn't be underrated. The cards however will have very little synergy. This is going to be a card that will require a lot of testing to see how it is best used.