I just had an issue with this, and did end up removing a .plugin item from the HAL folder. It is an item for a sound utility that I use, which now renders that utility unusable. So I had to break another program in order to get the Line 6 program to work, when it's worked fine on all other OS's for years. When I asked tech support if a fix was being worked on from the Line 6 end, the answer I got was (and I quote):
"The remedy to this issue is the procedure you already did. It doesn't impact a large percentage of Yosemite users but it does enough that we resolved the issue."
So, no permanent fix planned. Not our problem. Well, that's not great, is it?