I'm guessing I'm hosed but I thought I'd throw this out there in case someone else is having the same problem on PC. I can defeat sahrotaar & use my Bend Will Shout on him but it has no effect. I can't interact with him and he eventually flies off, heals, and attacks again. He never speaks to offer to take me to Mirak.
I've read over the various solutions to similar problems, uninstalling my mods and re-installing the game have had no effect. Anyone else seeing this?