I am afraid that ship has sailed. ISIS is uniquely evil, so much so that AQ hates them as well. The only course now is to be totally resolute and wipe them off the face of the Earth. Frankly I can't ever see Shia and Sunni living together in peace in Iraq for a long time in the future. Bush and Blair stirred up the hornet's nest in the first place but the West has absolutely no option left but to clear up the mess they started. Now that Russia and France are totally committed I can't see Raqqa lasting much longer, the towns and cities of Syria and Iraq still in ISIS hands are now finally being conquered. Surely anybody could see that ISIS have been intent on capturing all of the Middle East, the Maghreb and sub-Saharan Africa. They cannot be appeased, persuaded or cajoled.
Did you ever play wack a mole Tom?