Scramble isn't a spinoff. It's a full-on Sequel and calling it a warriors game is a disservice. It's not really. Playing the demo,the warriors comparisons stop after groups of enemies at a time. It's not waves of them tho like a warriors game. Plus like Persona 5 this has stealth elements. Some light turn based elements. They pretty much just made a sequel to Persona 4 that is an ARPG.
No comparison of two games is going to be dead on, unless it's a blatand ripoff, but if you're trying to describe it to someone quickly Warriors is the best analogy. Even if it has a new/continuing story, when the core of the gameplay isn't even really in the same genre, spin-off is apt.