Solas's original plan:
1. Trap the Evanuris within the veil. This much he achieved.
2. Use the orb to create an anchor which would allow him to step into the fade. Perhaps he could destroy the Evanuris there, while they were weakened; or even crush the portion of the fade where they were trapped, ending them forever.
3. Drop the veil, and work the surviving Elvhen to rebuild.
As we know, a number of things didn't turn out the way he planned:
1. He slept too long. Perhaps he thought he'd only be knocked out for a few decades, or even a century. The would wouldn't be that much changed from how it had been. There would still be Elvhen who could help him restore what was lost when the plan was complete. Instead, the world has fallen so far from what it was that he can't see any way in which it could ever recover, even if he could remove the veil gently.
2. He couldn't unlock the power of the orb. Hence he gave it to Corypheus, hoping that Corypheus could make the anchor, die doing so, and Solas could walk in and take the now-unlocked power.
3. Then the orb broke. This was the icing on the cake. Everything up to this point was something he could amend his plan to work around, in order to cause the least amount of carnage. With a romanced Lavellan, he seems almost hopeful for a time that he may be able to fix the world in a gentle way; he's still terrified to hope, but it's there.
What I think his new plans were upon waking:
Plan A: Similar to the old plan, just a few thousand years late. The orb is still intact. He can use the anchor to go into the fade, deal with the Evanuris and drop the veil gently. It will still cause some chaos in modern Thedas - ALL the magic coming back would do that to a world that fears mages - but it wouldn't be 'raining veilfire from the skies' levels of carnage. The people would learn to adapt. If Solas had recovered the orb after the battle with Corypheus, I have no doubt in my mind he would have then told a romanced Lavellan the truth and asked her to help him fix the damage he had caused to the fabric of the world. This was the optimistic scenario.
After the orb breaking...
Plan A became impossible. With the orb broken, Solas no longer has the power to defeat the Evanuris. It may be possible that trying to drop the veil without it may also be a far more violent process - a 'raining veilfire from the skies' scenario, with the addition of demons. (The shock the spirits would experience due to the veil being removed in such a manner would have to result in a lot of demons.) Between the Evanuris running around enslaving the mortal races, demons killing the mortal races, and the sudden violent sundering of the veil driving a lot of mortals mad, Solas could never go through with this. Here's where we come to...
Plan B: Time magic. Use the dropping of the veil as a catalyst to rewind time back to the instant of it's creation and prevent it from being created. The world he has been living in since waking wouldn't be destroyed; it never would have existed in the first place. To someone like Solas, who hates seeing others in pain, this seems like the kindest option after the orb was broken. Bringing down the veil would cause immense suffering... but people who never existed can't suffer.
This wasn't something Solas had considered prior to seeing it in action at Redcliffe, but I'd think he would immediately latch on to it's potential use as a last resort. By going back to the instant of the veil's creation, he may even be able to acquire his non-broken orb and use it to defeat the Evanuris, just as he'd originally hoped. The possibility of needing to do this was probably what prevented him from telling Lavellan the truth at Crestwood... and he tried to distance himself from her so that if it did come to pass that this was necessary, it would be easier for him to do. He tried to push her away because this plan would cause her to be wiped from existence.
If the 'magic is to come back' as Sandal's prophesy states, it's obvious Solas's 'Plan B' won't come to pass. Either he'll drop the veil and we'll kill him before he rewinds time, or Lavellan will change his mind at the last moment... either way, we get to spend a game repairing the damage caused by the 'bad' version of Plan A, including fighting the Evanuris. Either way, bring on DA4.