I’m on record as loving Gormek. He was the first red four-star that I maxed. I used him at tank early on because of his ridiculous HP. And they call him “the Hungry”. I can relate. Anyway, so I really like Gormek; I still have him at +20. And like @JonahTheBard, I don’t think Wilbur makes him obsolete in all cases. Sometimes, even his little bit of damage is preferable to no damage from Wilbur, despite his plethora of buffs and debuffs.
All that said, like @Gryphonknight, I value variety, and I’d pick Scarlett in your situation. Yes, she’s made of glass, but her tile damage is crazy high, making her an excellent choice for titans or a war team where you just really need to take out a green hero with your hit. I never count on her surviving or firing her special. She boosts red tile damage, dead or alive.
Also agree with @IvyTheTerrible that she is a nice place for your rogue emblems. Although I’ve given nearly every rogue emblem I have to Domitia, now that she is at +18, I’ve started giving some to Scarlett, along the attack path, naturally. Evade is a great talent for a glass cannon, and the competition for rogue emblems is generally sub-par. Disclaimer: I don’t have Jackal, and he would have been the choice if I did.