It was a surprise to me, and kind of a punch-line in a way, the -A, which then became institutionalized with the -D, -C, and -B. The resurrection of the ship, at least visually, matched the fact that they resurrected Spock in the prior picture. So it was a crowd-pleasing moment, even though it was also an economical choice.
When I saw Trek III I could have sworn they blew up the original model. That destruction sequence was very convincing, and I was perhaps just as worried that the magnificent model had been destroyed than the idea of the Enterprise as a fictional ship being destroyed. So I was glad to have that reassurance that the model was alive and well again, just with the -A added.
I also remember being very impressed by the new bridge with the first ever touchscreen okudagram panels. However, in retrospect I now prefer the tactile button look of the earlier bridge. The Trek VI bridge with its darker tones was a good compromise between the two.
Because the Excelsior was demonized so much in Trek III I always hated it. However, how it was treated in VI as Sulu's ship kind of redeemed the class. It still looked wrong as the basis of the Enterprise-B and was clearly evident as a cost-cutting measure rather than making a new model.