Even without knowing your roster, I will say that Scarlett is one of the better season 1 4*s. Her high tile damage is great for Titans, and her fast mana and attack debuff are great against bosses (many players only beat Ursena on hard mode because they used her, along with a defense buffer).
Having two Gormek will only be useful for War, I can’t really think of a situation where you would need two Gormek together on one raid team for example.
Anyone can think of a 4 star hero that has higher attack stat than Scarlett? I could think none. Jackal comes in at close second. Scarlett has more attack stat than most 5 star fire heroes. She is useful against green titans because of her tile damage. Like Jackal, they get to be more potent when emblemed and see them occassionally dodge at those special skills thrown at them.
Gormek. I have mine stuck to 3/60 when I got Wilbur. And another Wilbur got maxed. And another Wilbur got leveled to 3/60 while my Gormek is still at the same level. I will max my third Wilbur over my Gormek soon when i am done with some other projects.
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.