My speculations based on the season 2 trailer

  1. 4th character will be a guest. Who exactly is anybody's guess but probably someone popular enough to hype the general audience during the Game Awards.

  2. No more power crush heat engagers. I don't think it's a coincidence that they showed new heat engagers for Asuka, Eddy and Shaheen. All three currently have high power crush heat engagers. I think Bamco recognized that all these properties are too much and decided to change it.

  3. No more heat smashes wall splatting from 100 miles away. Once again, not a coincidence that they showed a new heat smash for Feng. He might get a situation similar to Heihachi where the heat smash will still wall splat, but only from close distance.

  4. More heat exclusive moves/strings. Steve is shown having a new string, which might be heat exclusive. Sorta makes sense considering his heat is lackluster compared to other characters.

  5. Anna as the 1st season 2 character. Not really a speculation, it's hard to hint any harder than that. Don't really care for her too much myself, but plenty will be happy I guess.