The whole point of the current state is to determine the outputs. If the next state determined the outputs, we'd call it the "current state".
Consider a traffic light. There are three states:
simulate this circuit – Schematic created using CircuitLab
The light starts out red (cars stopped). After a while, it turns green (cars moving), then after some more time it turns yellow (cars slowing), then red again.
It doesn't make sense to say "The state of the light system is Green, so the light should be yellow, because Yellow is the next state." You name the states according to their outputs. When the light is green, you call that state Green (or Go, or Drive, or whatever). When the light is red, you call that state Red (or Stop, or Halt, or...).