Farming for them is perfectly fine has long you enjoy doing games themselves... which i do plenty.
Am also lucky enough to always play with 3-4 buddies so a pug is really rare. The xp bonus makes a difference. And the mumble banter while we play only adds to the experience. Has much as i love sc2, this game has way way more appeal to the ''normal'' crowd, which makes it easier to play with buds for me. In the end, even if hots only opens the moba genre to me and i end up moving to dota2, so be it. For the time being, am getting more than my moneys worth.
Next buy on the list, Azmodan or Illidan. Am also tempted to save 10k to buy my master Rhegar skin.