Well, maybe you answered yourself why there's no happy ending to that romance, instead of wishful thinking?
Uhm...I'm not part of the 'happy ever after group' in the slightest - I'm all for drama, but drama with closure. My Lavellan certainly wouldn't have her happy ending, but I'm all for the bittersweet ones. (Fade romance buddy ending sounds very interesting, in my opinion. Or an ending where the Inquisitor has to give up the world of the living/her own mortality to join him, or something.) This wasn't an end to anything. It was a "Let me tell you what your people got wrong, then kiss you, then simply end it all." sort of thing. Without closure because our Inquisitor remains in the dark the entire time.
Don't you go around and tell me that wishful thinking is wrong, either. Solas gave us no time to tell him that we would still stay at his side, even through hell and back, because he thought it would be great to just leave without an explanation. He didn't want to hear it because he was selfish, in a way. And he even promised that everything would be made clear in the end. This is a game about options - why is it bad that we want options? Can't we possibly tell him "You are you and everything else doesn't matter." "I can't live with what you are." or "Let me prove that staying away from me won't solve anything, either." in a possible future DLC? Is that so bad? Does it magically break the laws of role-playing games?
Our Hawke could run off into the sunset with Anders. A male Warden could follow Morrigan through the Eluvian. Magical happy ending, even though everything seemed grim. Is it honestly impossible to think that a female Dalish elf could simply love him despite what he is and what he represents? Is it impossible to imagine an elf that can convince Solas that simply giving up on something won't solve anything, either? We saw pretty clearly that Solas himself was devastated after ending his relationship with Lavellan at the end. Do you really think these emotions will now simply fade away and won't haunt him anymore?
If you want to have a Lavellan that would worship Solas but wouldn't leave with him because he is a god, then that is fine. I don't tell you what your Inquisitor needs to do. But don't tell us everything needs to be grim, dark, dramatic and sad - and without a real closure. Because YES, I believe that simply breaking things off, promising to explain everything after the fight is over and then just vanishing into thin air is NOT a real ending. If you think it is, then that is fine - as I said before. But do not tell me and the other fans in this thread that wishing for another/real closure is bad. It is not.