For all intents and purposes Neo died, his body would not sustain an electrical surge like that. However his code was sent back into the source, we see that with the orange lotus symbolism. He attained final Nirvana, etc.
For all of Revolutions' hammy faults and essentially just being an extended 3rd act narrative wise, it's rich with metaphysics in the last half hour.
Whoever this "Neo" is in 4 is simply the same avatar, the machines are likely to reuse avatars all the time.