This one has me thinking. What if all troops had a built-in negative trait to set them a bit more apart? Things like:
Squishy - Take 50% extra damage from skull matches.
Slacker - Decrease attack by 1 after dealing skull damage.
Coward - Flees from battle when an ally dies.
Braggart - Reduce all stats by 3 when not placed in first position.
Hoarse - Start battle silenced.
Clumsy - Entangle a random ally after dealing skull damage.
Distracted - Lose 1 mana whenever an ally casts a spell.
Unstable - Deal 3 damage to all allies on dying.
Dying - Lose 1 health each turn.
Pain Link - Deal 1 damage to adjacent troops on receiving damage.
Mana Leak - Gain 1 mana less from [color] matches.
Mana Burn - Receive 1 damage for each point of excess mana gained once spell is charged.
Doomed - Receive a random negative effect after matching 4 or 5 gems.
Tainted - Immune to positive effects.
Tormented - Negative effects never expire automatically.
Yep, I know, looks utterly horrible at first. I mean, who would really want a Squishy Goblin or an Unstable Goblin Rocket, right? It would allow for some extreme buffs to balance things out though, like giving a Dying troop a very high health pool or an appropriate spell (deal missing health as damage to target, restore half missing health). Wish there was some kind of sandbox for weird game rules, like the Tavern Brawl in Hearthstone, I think I’d enjoy giving it a go.