The easiest solution would be to allow us to activate/deactivate weapon upgrades once we bought them, somewhat similar to how we pick talents. Don’t like your Mang to lose you Boss Raid battles? Deactivate the Warm upgrade. Don’t like your Dawnbringer to mess up the board? Deactivate the Dawn and the Hot upgrade. Feeling lucky with a fireworks team? Activate them again.
Yes, that’s the lazy way out, I’d rather see some upgrades that help you more than hurt you. No point in addressing it again though, the last dozen times or so the topic was brought up the devs went into hiding.