If your online for Baal/Cerb an interesting hero to work on is Thucydides. His cards are cheap and they are easy to get on "Tavern Tuesdays". I kept only skill hits and Criticals (got 3, 1 gold 2 purp). He does very nice damage and criticals a lot. After you do well in Baal/Cerb you can get more coin and credits, helps a lot to buy more cards for other heros. I Used about 200 cards and a bunch of gems but if you decine early saints it keeps the cost in gems down.

For other hero's I favor Criticals and offensive over defence or HP. Dodge and Block can help a lot for PvM in Heroic Realm and Quest Bosses as they all can be dodged and blocked fairly well. Hit saintings for Mages.

Gordo

We have 1 player on our server with 4 gold criticals on his Adam, it rocks :-)