Iāll chime in here since Rookās isnāt ready! Sheās fantastic. Iāll go by game phases:
Titans
I actually think she has a place here, barring a surfeit of elite level options. Currently, I roll out (firing order): Mist, Jackal, Leonidas, Joon, and Wu Kong. Reasonable tiles, the mana slow is a desired effect and has good synergy with Leonidas (and this is critical, since I canāt really afford to have the titan fire their special much as I have no healing on the field), and making other specials hit harder isnāt nothing. Sure I would rather have 60-70 more tile damage, but thatās not an option for my lineup.
I realize some feel sheās a C grade at this task and I can understand why if you have Vivica for team survivability and, say, Musashi. But for less god-tier rosters sheās very viable and a better option than Gretel or Onatel (which are my alternatives). B grade in my mind.
Defense
Hard to say as I donāt encounter her in that role much / at all. So obviously not super well suited to high level Diamond defense. I mean, what 4 star is? Iām going to reserve judgment on this until thereās a four start tournament sheās likely to show up in.
Intuitively, Iād venture sheāll be good but not great. I mean, she strikes me as a better Little John. Desired effect, but one that wonāt get max value due to AI stupidity.
Offense
Iāve used her a decent amount in Diamond raids and sheās robust enough at +6 that she often fires before dying. And sheās the right speed (her defense down vs. specials) to easily get synergy from the rest of your yellows or whatever else you brought. I havenāt really found I want to displace Jackal, Joon, Onatel from my anti-Kunchen team, but she excels against other purple tanks and in mionor stacks with Joon. Superb attacker, a lot of fun combinations possible.
War
When Iām churning through my last flags with the lesser part of my roster it is really nice to know I can field Mist with, say, a Sonya or Caedmon type and have a reasonable shot at getting a snipe kill. Iām sure YOU get this, but to make sure Iām being clear for other readers - it is HARD to generate kills with your last flags and heroes that can do it are much more valuable. Which is why she fights in almost every war, where a hero like Costumed Skittleskull (slow + full AoE = more total damage but no kills, which is often an undesirable trade) often stays benched.