Am I the only one who doesn't hear a Kill 'em All vibe from anything except Spit out the Bone? They're actual return to thrash was Death Magnetic. That album was a badass thrash metal album.Real back to the roots stuff.
The new album is amazing as well. But I don't hear much thrash. There's the impression being given out that it is like their first few records, but to my ears it's much more like the Black album, or even a heavier Load at times. Which certainly isn't a bad thing.
I think it was Kirk that said the new record was like KeA... Based on his track record of comparing new material to old material, I wouldn't give it much thought. He seems to have a weird perspective of that stuff. He said DM was like Justice....
As far as the new album, stylistically, I have said here before, I think it's a mix of everything from their career. There is some thrash (Hardwired, Spit) that throws it back to their earlier days. Even a song like Halo could have been on an earlier record. Tunes like Moth and Revenge could have been Black Album material. Stuff like Dream and Savage are more Load-ish...
Basically, I think it's a balance of all the styles they have touched on in the last 35 years.