Hearthpwn

This is both a good and a bad Idea, if I DE cards from other classes I'd probably find it hard to complete missions, which translates into lost gold, which translates to NO arena, which lastly translates to no dust (probably) + expert packs from arena keys. 

Actually, you should choose a number of classes (2 or 3) that you don't want to play, and DE all cards for those classes. Try to have at least 6 classes that are good enough to complete your dailies (possibly in casual mode) so you can earn gold, buy packs/arena and get those epic cards for your chosen deck.