I suggested a character restoring AP or punishing for stealing AP in the past, and these suggestions seemed interesting to devs.
Now my suggestion is for a character with a passive which makes him immune to stun at the start of the battle.
Then, when a enemy tries to stun their team, either this character reflects the collective stun to the enemy while preventing stun to their team, or this character delivers doble the amount of special tiles they would spawn usually (that means this character spawns special tiles at the start of the battle).
A character with a passive like this, and doing it like I explained on the first option, would restore BRB and grocket, and then kitty and Polaris, plus Wong and magik.
Although it seems a bit weird that 3 characters would be needed to fully counter chasm, this character with this skill could enable the release of more characters stunning at the start of the battle (making the importance of having these characters doble, by the way).