LW is one of the hardest to pin down. As much as I hate him with every fiber of my hater being, BJ had the legit claim to greatest LW of all time for a number of years. The recent crop of LW champions have some extremely impressive resumes. It's really hard to nail down without a champion with like six plus defenses but that's because LW is the deepest division in MMA bar none. The competition is fiercer than anywhere else and the difference between fighters as razor thin as can be.
Khabibi shouldn't be anywhere near GOAT talks until he's taken out the actual LW champion Conor and the bigger threat in a much more diverse skillset Tony. He runs through them (and I have no doubts he will), slaps around Eddie a couple other LWs, he'll be something to the tune of 30-0 with five defenses. At that point not only will he be the unquestionable LW GOAT but he'll be angling for MMA GOAT if he can match or exceed GSP's title defense record with 0 Ls.