Sorry to sound negative, but I really don't see the council spending any large amounts of money on this route. They will look at the evidence, and then go for the cheapest short-term solution.
After all, how many times has this road been closed since it opened? Have the last two severe winters exacerbated any problems with the freeze-thaw action on the cliffs? What are the chances of prolonged closures in the future?
This is the first unplanned closure of the road I can remember in recent years, though it does need occasion closures for maintenance work on the rock face (drilling loose bits, bolting, replacing netting etc).
Since the road was built it has been known the rock face was unstable and it has always been a case of managing it with ongoing maintenance rather than ever expecting a permanent fix. I can't see this case being much different.
A completely new route for this section of the road was considered in the past but as it required such a distance of completely new road which would obviously have to be built in one go it was decided it was too big a spend for this route. To just improve journey times on the route it would be much more cost effective to upgrade other parts where a simpler engineering solution could be reached.
Work colleagues from Inverness used to use that route mainly because the A82 down the side of Loch Ness is so poor.
You can make decent progress between Inverness and Invermoriston providing you don't get held up by slower traffic, it just lacks overtaking opportunities. The A832-A890 route is quicker by car because you can more than make up for the slower bits on the faster bits. It's slower by lorry though as you can't go any faster than you can on the A82-A87 and the slow bits are very slow by comparison.