I LOVE having spooky S1 Locke back (even if he’s dead). I think the writers gave us a peak of his potential in the first season and then spent these past seasons showing his journey to get back to that place.
Some religious doctrine (I forget which, though it may be multiple) says that a soul has to journey through mortal life only so that it can return more enriched to its maker upon death. That this is the purpose of our existence, why we learn, love, suffer, etc. Interesting.