What did the restart of the Avatar Cycle mean?

I'm writing a fanfiction for the Avatar after Korra(not Genji my own oc) and when I began thinking about stuff like the Avatar state, and how he'd interact with his past lives that got me thinking: if the Avatar cycle started anew then would the past lives be gone? I checked and the majority said yes. But then I remembered than LOK isn't particularly as liked as its predecessor so I'm asking you this: what was the narrative purpose of the cycle starting anew? And whatever it was, if it was a good or bad choice on the writers behalf?