A lot of people at the Hearthstone subReddit are finding the Arena different with the addition of GvG. It seems to be more aggro-oriented now as with the increase in the number of cards, getting board clear spells seem harder. I think that could be random but I did draft a Mage with only 1 Fireball and 0 Flamestrikes from the free Arena ticket run. Anyway, here are the threads on it:
Aggressive player's helpful advice
I am immediately so much worse at Arena
A HearthPwn's recent article has a nice section on GvG deck concepts. They are mostly Mech-themed which is really what the expansion is "shaping" decks into with all the Mech support and minions in it. There were quite a few decks that are quite budget-friendly IMO with minimal Legendaries used:
Warrior's The Assembly line by TheChiv
Mech Shaman by Nuba
Beasty Zoo by Sparkaz
Mechanical Zoo by Sparkaz
I think there is definitely room for more tinkering but those are some nice templates to work from.
