Here's a thought exercise. I think we can all agree that giving the orb to Cory was NOT GOOD.
What would have happened if Solas *hadn't* given the orb to Cory?
No explosion, right? Right. Would the mages and templars have stopped their war? Maybe. If yes, no Inquisition. If no, Inquisition gets formed with Divine Justinia backing it to stop the mages and templars - at least so Cassandra implies.
Cory doesn't just disappear. He's still planning to take over and make himself a god. He has the Venatori. He has the red lyrium. He probably even has the Grey Wardens. Most likely, he's STILL planning on assassinating Empress Celene and invading with a demon army. He doesn't NEED the orb for any of that. What does he need the orb for? Entering the Fade. What does he do without the orb? Looks for alternate ways to get there.
Without the explosion at the Conclave, no one knows what Cory is up to. No one even knows Cory exists. Cory is pretty much free to do whatever because no one is trying to stop him.
Obviously a great deal of this is conjecture, which is why it's an exercise in thought.
So, what does everyone else think Cory would have done without the orb?