I've read several interconnected fan theories that rely on interpretations of Palpatines words in that scene.A few thoughts about the title and that enigmatic trailer.
After Episode III came out in 2005 and fans tried to find new ways to dissect the film they had already watched dozens of times to keep it fresh in their minds, a theory started to gain traction, fuelled by the opera house scene between Anakin and Palpatine.
In that scene, Palpatine recounts the old legend of a Sith named Darth Plagueis the Wise (actually a real character and Palpatine's first master) who would have found a way to manipulate the Force in order to "create life". As Palpatine says those very words, he turns to look at Anakin and smiles. Interestingly, they have this conversation in front of a ballet involving minuscule (from their POV) dancers with long costumes trailing behind them, seemingly flying or swimming through a gigantic bubble (evoking sperm racing each other to enter an egg). The assumption at the time was that Palpatine somehow knew that Anakin was the result of Plagueis' manipulations of the Force and that his mother, a poor slave, had somehow been impregnated by the Sith Master in order to create a being so powerful in the Force he would be able to annihilate the Jedi Order and give the Sith their revenge (which Anakin almost managed to do when he became Vader). The theory further explained Palpatine's strange obsession over Anakin as his desire to reclaim his old master's creation for himself to fulfil what Plagueis couldn't do, therefore proving his superiority. But however powerful, Vader was a diminished "ultimate Force user", not just because of his multiple debilitating injuries but also because of "the good in him" that Luke was able to call upon to turn him back to the light side and prevent the decade-long Sith's plan from coming to fruition.
However it's possible Anakin was not the only product of these Sith manipulations. What if Rey too was an experiment? She seems to fit the bill: Poor slave girl growing up on a backwater world where nobody will ask questions, born to nobodies - check. Intuitive understanding of the Force and ability to overpower other Force Users who have been training for years, check.
Rey could very well be Palpatine's own attempt at bettering his former master's experiments and creating an ultimate Force User to serve his dark purpose. If Anakin was Plagueis's 'son', Rey could be Palpatine's 'daughter'. A being born of the Force but unburdened by Anakin's severe injuries and his love for his mother and wife. True, Palpatine died before Rey was born but he still may have planted the figurative seed that grew into Rey before his death.
Interestingly, this trailer ends with Palpatine's satisfied laughter, as if to say that his shadow still hovers over the entire story, or even maybe that he finally gets what he wanted in that film... The rise of his very own Skywalker, maybe?
In the new EU, which Disney oversees to ensure the books, films, comics etc. all fit neatly into one canon, the term "Skywalker" is explained as originating from the mythology of an old race of beings who knew nothing about the Force but realised that some amongst them were able to call on supernatural cognitive abilities to pilot or guide their ships along dangerous space routes by seemingly sensing danger before it was encountered, hence "sky walking" their ships to safety. These Force sensitive people, for lack of a better term, were called Skywalkers. Of course, Anakin is often described as one of the best pilots in the galaxy, and both Luke and Rey exhibit the same natural talent when flying ships, even for the first time (Luke in A New Hope, guiding his X-Wing through the Death Star's trench, and Rey with the Millennium Falcon in The Force Awakens, skilfully evading a squadron of TIE fighters through the dunes and wrecks of Jakku).
If the name Skywalker originates from this ability in the new canon, it's entirely possible that the name in the title is not to be taken literally but could rather be referring to the title or position of that individual who is able to guide others through the sky with the Force as their ally.
A final thought? That old race which named their Force sensitive pilots Skywalkers is called the Chiss. The most well-known representative of that race in the Star Wars canon is none other than Admiral Thrawn, one of if not the greatest of Palpatine's military advisors and strategists.