Long before Planetside 2 was officially announced, Sony Online Entertainment had been teasing "Planetside Next." Apparently, the long-in-development title was originally planned to be a free-to-play update to the original Planetside, with a graphical update to modernize it. A PC Gamer report from SOE Fan Faire reveals that "once the team started working on the project... they got so excited about its potential that they decided to scrap their plans and make a full-fledged sequel instead."
Had SOE stuck with their decision to make Planetside Next a F2P first person shooter, it would end up competing against games like Tribes: Ascend. Sony Computer Entertainment also experimented with a free-to-play trial with their own massively multiplayer FPS, MAG.
Planetside 2 is admittedly very early in development, and one thing SOE promises to offer for the sequel is more transparency with the game's progress. The company plans on introducing a "three year plan" to gamers, one which will cover all the planned changes for the game, including expansions and updates for the first three years after launch. Given the drastic changes an online game can experience over time, the "three year plan" should hopefully give gamers a better idea of what's coming down the pipeline and, if need be, offer feedback before an update gets implemented.