The Frasier reboot will finally have an opportunity to fix the issues in Lilith's relationship with Frasier. Despite there being no confirmation on Bebe Neuwirth's return for the continuation, if her character Lillith does make an appearance the show can explore a new version of her dynamic with Frasier. With Frederick moving on from school, there might be an opportunity for the relationship to be very different from the original show.
A spin-off of Cheers, Frasier follows the character of Frasier Crane melodramatically dealing with his family life and career with Bebe Neuwirth playing Frasier's ex-wife as the only recurring character from Cheers to appear in the series other than star Kelsey Grammer. The pair have an intensely competitive yet fond relationship that withstands long distance in an attempt to give their son Frederick a good childhood. Lilith comes to Frasier in season 10 episode 13 "Lilith Needs A Favor" in hopes of having another child with him without revitalizing their romantic relationship. When Frasier ultimately refuses her offer, it is implied she employs the help of another suitable man to fulfill her desire. This is the final major milestone of their relationship in Frasier.
Frasier comes to Cheers fresh off a divorce which could lend to his stronger irrationality on the show and how he begins a turbulent relationship with Lilith which ends due to poor compatibility. In his own show, they emulate a hand full of tropes divorced couples in sitcoms do that occasionally affects the life of their son, Frederick. This is seen in Frasier episodes such as “A Lilith Thanksgiving” where the perfectionism they inspire in each other ruins his chance to go to an elite private school. Despite being on good , the bad influence they had over each other in their marriage vividly lingers in their parental dynamic. The prospect of a reboot, especially with their son potentially being in college or past it, allows the opportunity for Lilith and Frasier to overcome their misgivings about Frederick’s path in life, as well as other issues that made Lilith's original characterization so bound up in the couple's dynamic. This in turn may affect how they view each other, for better or worse. The revival can't repeat the problems Lilith brought into Frasier because many of those problems hinge on Frederick's upbringing, limiting her as an individual when she is in and of herself ripe for development.
While it's unlikely cameoed by Star Trek's Brent Spiner, there's a possibility Frasier will fall into fatherly habits depending on how near Lilith is to him and how close of a relationship Frederick has with the new sibling. Though this may catapult their dynamic back to a stormy square one, it could also imply Lilith and Frasier will work on what they failed at in their attempts to raise Frederick perfectly in Frasier.
Regardless of the convincing façade of animosity between Lilith and Frasier, there is a remaining love there that could expand their friendship in new ways in the reboot while simultaneously fixing the issues they shared in the original show. While Bebe Neuwirth isn't confirmed to return, she is undoubtedly a face that should be shown in Frasier Crane's life nearly two decades after the Frasier finale. What type of dynamic they will be sharing in the revival is unknown, but if Lilith returns to Frasier the previous problems with her character cannot be repeated.