Should I turn my Mage/card summoner into a Hacker? My Godhand and samurai are dealing good damage but my mage feels like the weakest link if he doesn't get the right cards.
I would hold off. At first Card Dudes seem to be underpowered in comparison to other classes.
Then you see what synergizes with their abilities.
I'd focus on stuff at first that gets more cards in your hand or lets you pull more cards and then see what abilities benefit the most with card usage. Like, if you think fire is the way to go then focus on getting as many fire cards in your hand as you can and using abilities.
When I combo'd all the Duelists fire abilities with a Agent's fire hacking I was outputting ridiculous damage every turn. Stuff like making an enemy weak to fire, hitting them with a fire attack that then auto-uses more fire damage after it, have a fire attack activate at the end of round based on how many fire cards I've used which then has a fire attack activate after it. Basically getting four attacks a round that get progressively stronger every round.
I'll also say that trap cards are way more useful than you think and that if you can actually pull of getting all three traps to hit an enemy to activate Judgment, even at level 1 the damage it does is fucking stupid.
I really loved my Duelist. My first party was Godhand (fucking stupid powerful on their own), Agent (incredibly good synergy, go either hacking or guns because both skillsets are really REALLY good. Hacking for survival by letting you pull MP or make enemies not hit you, guns for...attacking like 30 times a turn) and Duelist who I used as above. Pull fire cards, drop fire spells and watch the damage rack up.
I adored this game. Def in my top 10 of 2016