The seacabs have been gone for a while now. Some early rumors mentioned the possibility of total removal of the ride system so that the tunnel could be used as a walk-through observation area. I have heard nothing new about those plans in over 6 months.
Living Seas makes me so sad. That attraction has such potential! Disney has always taken risks and created uniquely themed attractions. It just pains me to think that a Disney Imagineer couldn't come up with something outstanding for their sea life attraction. Where's Walt when you need him?
I know its not one of the most sought after attractions but it's one of my favs. I was looking forward to taking Ds on it this trip. DH and I did the Dolphins in Depth Tour the last time we were there and it was fabulous. Worth every penny. I am going to miss the ride.