The LW company closed to my knowledge. The devs parted ways to other good paying jobs. The devs presumably signed agreements not to pursue any kind of file-sharing development in the future.
LW 5 did have some improvements over LW 4, most notably the interface. But as a whole, LW 4 had a bundle more tools and options for the user. And I have always missed those tools. LW 5 was simplified down so to speak, which is fine if you don't know much about these kinds of programs. But for the experienced users, they wanted more tools and options.