I am SO pumped for Bo Rai Cho. He was one of the characters I was hoping for the most but also expecting the least. I kind of dropped MKX before I tried to get competitive with it; Bo makes me want to pick it back up with him as my new main.
Tri-Borg is an excellent choice, goofy name aside, and BarakAlien looks great. I give zero shits about Leatherface, it should have been Fujin instead. Hell, if you're going to do two guest characters, why not bring Freddy back for the vs Jason dream match? Is anyone at all actually excited about Leatherface? Oh well.
Overall I'm more excited about this pack than I'm not, and it's probably going to be a purchase next year. The nebulous "2016" release date is concerning, though. You couldn't narrow it down to Q1 at least?