Legion has eclipsed Sigmar and X-Wing, though I think X-Wing will likely see much increased sales once Second Edition comes out. Many Legion products are sold out, even from
FFG, and are being reprinted - as usual
FFG's logistics is letting them down a bit, with at least one unit (Fleet Troopers) purportedly selling out at the distributor before even releasing!
Losing Netrunner and the
GW licenses has hurt
FFG but they still have quite a broad catalog of products. Losing the Star Wars license (
IIRC up for renewal in 2020) would be awful for them. They're focusing a lot on L5R stuff recently because they own that license, and I've heard rumors they may try to expand Twilight Imperium content also. Their fantasy universe, Terrinoth, seems broadly unpopular.