Some things can be finished quickly. Some things take time. The Lightning Returns: Final Fantasy XIII logo, it seems, took time. A lot of time.
On the game's official Twitter, someone from the Square Enix publicity department said "it took an exceedingly amount of time to arrive at the design". Creating it was a long process of trial and error and took "a long time"; this symbol was inspired by the motifs of metal and lightning.
After saying that the symbol does appear in the game's story, the PR person asked people on Twitter what their thoughts about the logo were.
While some did say they liked the logo, others said that Square Enix needed to develop and release games faster. Others brought the inevitable complaints about Final Fantasy Versus XIII being M.I.A.
I've always thought the Lightning Returns logo was somewhat reminiscent of Skyrim's logo—not necessarily a bad thing! But, as Lightning Returns: Final Fantasy XIII producer Yoshinori Kitase previously told Kotaku, "There is no relation to Skyrim whatsoever." The logo was designed to reflect the newness of this game. Full stop.