at least on my Nexus 7 (2012). The game is lagging very strong, terrible FPS problems. Perhaps improved with this Android 5 when it comes out? For this driver, the app my knowledge was designed. Hopefully Blizzard upgraded for older devices after.
My advice: let Hearthstone run on PC and stream via remote connection on tablet, for example by means of "Splashtop" works much more smoothly.