Are u sure? I dont think this is an old algorithm. I had at least a dozen planets in one earlier PW. Planet influence used to be measured overall by faction but also broken down into personal influence and the person who personally contributed the most ended up controlling the planet.
This is the first PW where not a single person has more than 1 planet. I agree that planet ownership is somewhat meaningless but I think it's still very important just for the way the game feels and how fun it is. If I'm not mistaken, planet ownership still determines whether or not you can buy/sell structures for this planet right? Apart from faction leadership who can control every planet.
It's a bit like the metal situation, everyone has control over the metal they personally earned and could waste it on some dumb thing but it would be best for the faction if they just leave it alone and let leadership use it. It is still important I think to have that feature because there should be reward for contributing more and it let earn your way into the PW big picture. If someone wins 20 games, earns 1k metal and 5 planets for the faction, they should for sure control a slice of the PW pie.