Balancing is great indeed.Imo there was a fact that damaged arena: the born of sites that give parameters to cards.Many players used these applications and learned the values of cards as in chess the rook=5 (for a beginner).This reduced the number of totally unworking decks and also very sperimental ones.I think the meta should bet on "enhancing cards" pushing n a direction direction where there are more cards as Hobgoblin or Aviana that give shape to your deck. There could be more races (murlocks, pirates, beast, mech) and also cards that enhance mechanics humbing elemental, pirates.Also cards that benefit from having more than one (or two, three, FOUR!.. and so on) copies in your deck i think would be fun. And also make some show!I go back into my cave.
I like the idea of keeping the GvG packs. I will go further and i will keep one pack from each card update. In a few years pack opening menu will be like a museum of retired booster packs!