Let's talk about a hypothetical scenario for a moment.
I sometimes see people saying they hope their Lavellans can help Solas with his plans. If his plans are indeed to release the rest of the elven "gods" (that's the assumption for the scenario).. can anyone in this position explain to me why they [their Lavellans] would do that? Is it for love? Releasing the gods seems like a terrible idea to me lol.
All my Lavellan's, through talking with Solas really start to get a sense of how much was lost and how desperate the situation is for the elves in Thedas, this is something that develops throughout the game. So if what Solas is planning is ultimately for the greater good of the elven people they're likely to support that, because the status quo is not working for them and they will be truly lost forever if something doesn't change.
If Solas' plan involves restoring immortality and magic to elves it is something that goes against something that he holds dear, he'd be going against their free will and imposing his own upon them without their knowledge or consent. but that doesn't mean that its not the right thing to do. I don't think he's planning to release the gods, but he might be planning a one way trip to wherever they are to achieve a goal, without enough power to ever return.
But did Solas break it off to "protect" Lavellan? That's the cliche crap you usually see that's supposed to be all noble and romantic, but what I took away from it was that he couldn't bring himself to tell her the truth for whatever reason - and then couldn't continue on with her while being dishonest. It was his choice to make, so good for him... but I don't get the "I left you to protect you" crap. He left her to stay true to himself and his goals.
I think he left to protect himself, not Lavellan, she was a weakness and a distraction. He apologizes for distracting her, but really he's apologizing for letting her distract him... DICK! 
Of course when he broke up with her, his plan involved the Orb and may not have involved leaving her like he did if it had survived.
Scenario #1: DA4 with new protagonist. Solas dies alone (either killed by new protagonist, killed defending new protagonist, or self-sacrifice to save blah blah blah). Lavellan doesn't know. She's barely mentioned except in the final moments of his last breath. Woo.
Scenario #2: Solas dies in Lavellan's arms. Either she had to kill him, he was killed by blah booty blah, or he did self-sacrifice.
Scenario #3: Solas kills Lavellan for her mark in DLC or at the start of DA4. New protagonist comes in and repeat Scenario #1.
Scenario #4: Lavellan sacrifices herself for Solas. She dies in his arms. He like probably tries to send her spirit into the Fade or whatever so she can live on and he can eventually join her.
Scenario #5: Lavellan and Solas die together. How and why, no clue. But they're dead. At the same time. Hoo yah no dying alone.
Scenario #6: Lavellan saves Solas and together they go into Uthenera once their business is complete.

NO I need some more happy choices.... ya sicko! 
My one hope, regardless of how things turn out overall, is that Solas continues to exist. I can only speak for myself, but I find his potential story scope to be quite wide, extensive. Like Flemythal, he has existed in the mythos of these games/books, longer than just this single entry. To have him die (killed or otherwise), just seems...anticlimactic. A limited resource, when he could be more.
Not saying he will be, simply hoping.

Agreed, I think it would be lame to have the Dread Wolf get killed off after introducing him, and I just don't get why Lavellan being part of his world can't happen. I've no care for them running off and having kids, but getting back together and working to restore the elven people would be grand
.
We've had the sad chapter, now can I get the redemption and hope chapter please Mr Weekes.