My entire party was stunlocked to death during one fight. I killed all enemies except one mage, and he just kept casting rain and then using an air wand. My entire party was close enough together to all be in the puddle, and were actually all at full vitality when this began. Every turn, my entire party was stunned. I did end up winning the fight, because The Red Prince of Bel Air had Comeback Kid, so when he died, he popped back up unstunned, so I was able to get him out of the puddle and resurrect someone. Still, I feel like that shouldn't have happened.
The flip side is that, with a full party, I can keep all enemies CC'd throughout the entire fight once I get their magic armor down. That's actually how my entire party was still at full vitality in the fight described above (I didn't use heals until after everyone died).
In short, I feel CC is overpowered at the moment, particularly lightning (since you can just wand it out without cooldown into a puddle). Combat is more like a CC management sim than a strategic battle.
My suggestion for a resolution would be to implement a weighted resistance chance. If you get stunned, your chance of being stunned is reduced. If you get hit with a stun and resist it, your chance of being stunned is increased. This would prevent stunlock without sacrificing strategy to the RNG gods.