OH GOD.
I pretend the time travel stuff didn't happen. Please not in Dragon Age. I hate time travel... I hope Cole just meant that the people in current Thedas have become real to him and that it complicates things because his plan will make them suffer. Because he was asleep so long the waking world seems like a nightmare to him. A nightmare he created and wants to wake up from by correcting his mistake. But now that he's grown to care for this nightmare version of his former reality, where does that leave him? Solas is deeply conflicted now. But he did choose his crusade by turning away from Lavellan. He will not seek her out again. He cannot afford to have doubts. He's severing his emotional connection to be able to carry the burden of his actions once again. So I get the uncomfortable feeling that we will not like his plan...
I too see him as a more radical emotional and therefore messy version of Morrigan. They are both arrogant know-it-all but Morrigan has a much better grip on her emotions and has way better intuition. Of course she doesn't carry his burden... but right now I'd much rather put my fate in her hands.
I agree about Solas and Leliana both being the end justifies the means kind of people. To me they represent the dangerous dark side of idealism brought on by disillusionment. Leliana has a crisis of faith while Solas has a crisis about society. They hate the world as it is right now but do care about people a great deal. Both think radical change is necessary. Both are in an angry dark place in this game, and both can be softened up a bit.
I hope it will matter later if the inquisitor impressed him or confirmed his prejudice.
I actually see Solas as a wiser, more competent version of Morrigan who has a much better grip on his emotions and far better intuition. 
Morrigan's had a lot of 'Stupid Evil' moments throughout her screentime, as well as intelligent ones. Being raised by a cackling elf god riding shotgun in a cackling apostate troll-grandmaster tends to have that effect. She's rather arrogant about her knowledge of ancient magic and elf language. Solas corrects her and she gets indignant. Solas is contemptuous, but honestly, I would too if I was a god and someone was boasting about how much they knew while getting so much wrong.
Inquisition lets us see one of her biggest mistakes, (Dismissing Mythal as either dead or non-existent, then accidentally binding herself to the one person she was trying to flee.) I loved that Inquisition showed us Morrigan completely screwing up, as well as standing up to Flemeth and having great moments. She's one of my all-time favorite Bioware characters along with Solas.
Solas is definitely the more radical one, though.
I guess a lot of this is just me getting bored of making fun of Solas for being Hawke x10 when it comes to screwing up.
We don't know what he actually did. We just have wonderful theories. It seems like Cole supports him as being right, whatever it was.
Then again, the 'you did it because you had to, not to be right. But you were right,' suggests he was being kind of an arrogant know-it-all about it. 
I kinda see Solas as a much older, more experienced version of Morrigan that was defined by his allegiance with his mother figure Mythal instead of his rebellion. (Ironically.) A version of Morrigan who had to do much darker deeds.
Definitely in agreement about the Solas Leliana parallels. 
I also despise time travel outside of Doctor Who, and even then it can wear on my patience. But it's the best way of looking at real I've seen so far, which worries me.
Then again it will all be worth it if we can travel back in time to mess with the Dread(Locked) Wolf, Mythal, and Solas all at the same time.