So here's a thought:
Each player has two decks, a Hero Deck of Heroes, Classes, and Equipment and a Challenges Deck made of Monsters and Traps. At the start of play, each player randomly selects ten cards from their Hero Deck, this becomes their Treasure Horde. Each player draws X cards for their starting hand and places the top card of their Challenges Deck up. The Challenge Cards have an obstacle to be overcome with a list of requirements the Hero must meet to overcome it. A Trap Card might read: Disable Device 5 OR Magic 10 OR Strength 18 AND Health 50. meaning a weak thief hero might bypass it easily, a Wizard or Cleric might need to be of moderate power, and a Fighter would have to be fairly burly. If a hero can't bypass a challenge, they can be permanently buffed by playing a Class Card (Class Cards would be something like, Rogue +2 Sneak, +2 Disable Device, +4 HP) or temporarily buffed for the challenge by playing an Equipment Card (10ft Pole +2 Disable Devices, Flaming Sword +2 Strength, Wand of Armor +2 AC +2 Magic). Equipment Cards are discarded after solving a challenge. Once a player defeats a challenge they draw one of their treasure cards, discard any equipment cards on their hero, and their opponent plays another Challenge Card from the top of their Challenges Deck.
Heroes are used to acquire Treasure by solving Challenges.
A hero's stats are determined by their race, class, and other sundry bits.
Classes are played on heroes to upgrade their abilities. Once a Hero meets the requirements he's eligible for a Prestige Class card, like Elf, Arcane Spellcaster, Martial Class, you can play Arcane Archer on them.
Equipment is expended when solving a challenge but allows anyone to solve any challenge if you're willing to spend the cards to do it.
Traps and Monsters:
Traps and Monsters provide the challenge for the other player to overcome.
I haven't come up with an elegant way of removing heroes from play yet. Maybe each way of bypassing a trap or monster has a HP Cost that is deducted from the hero's total. You can play, like, Potion of Cure Light Wounds to pay the cost for you but it isn't avoidable otherwise.