I'm just as frustrated as you are. And as far as I recall the same scenario played out when windows 8 was released. UX1 didn't work correctly for weeks or even months.
Line6 seems to be a company that is "reality-resistent". Windows 10 was released 20 days ago yes, but it was announced a year ago with previews being released for developers ever since. So Line6 has only themselves to blame for not getting their drivers ready just in time for the official Win10 release.
Maybe it's a hell on earth to keep drivers updated for so many products and maybe it's expensive but that's really just to bad. If a company want lots of customers and keep them happy forever then updating product drivers for new OS version at release date is good business and a blessing for the accounting department in the long run.
Now answering your question: IK multimedia has some nice alternatives but my guess is that they to are not 100% Win10 ready at the moment.