So this week in RPG-land I've heard that PAIZO is ditching the Drow for a whole host of reasons including how the Drow are still linked to IP controlled by WOTC. Here's the best reason to ditch the Drow... they aren't interesting anymore.
Drow were once interesting but they became boring as we learned more about them, they eventually became little more than dark-skinned leather fetishists with the pretense of matriarchal society. Once upon a time they were the bad guy elves who had to retreat from the sunlit world and were so rare many doubted their existence and somehow because a faction or two of Drow were the primary villains in an early popular series of modules they ended up everywhere including the first Monster Manual follow-up the Fiend Folio and and later as a player option in Unearthed Arcana. They became the rebel-cliche cool kid choice for rebel outsiders among PCs and got boring.
Paizo ditching them in favor of something else is a sensible enough choice, go for it, not every campaign or game needs the same set of options; even TSR has an entirely alternate take of deep dwelling weirdo elves with the Shadow Elves of the Mystara and Hollow World setting(s) in the D&D line that was playable and distinct, you can too.
The concept of light elves and dark elves has it roots in the mythic fiction RPGs draw from so they have a place in fantasy RPGS. In my own current campaign there are Light Elves, Dusk Elves, and Dark Elves and what makes them difference is their connection to the magical realm of Faerie and their personal allegiance to the ruling forces of Faerie. Light Elves are aligned with the Seelie Court, Dark Elves are aligned with the UnSeelie Court, dusk elves have no allegiance to either. In the campaign this means Light Elves and Dark Elves are effectively immortal and can not be permanently slain within the realm of Faerie; Dusk elves are mortal within the realm of Faerie and the Earth having tied themselves deeply to the mortal world or separated themselves far too much from the Faerie spark maintained by the Seelie and UnSeelie courts. A lot develops from this conceptually simple setup and it ties to a loose connection to myth and fantasy. Dark elves can be something different from the Drow and still have a place in an RPG campaign.