There is absolutely no problem in feeding a dog only dry food. They don't have a problem with fluid intake, so if only fed dry food, they will drink more water to keep hydration levels up.
There are particular "natural" nutritional benefits in wet food (eg. Vitamins and Minerals), however an only wet food diet can lose the benefits associated with chewing, as wet, soft food doesn't massage the gums. This helps with teething and dental cleaning.
So it really depends on a variety of things, and the lifestyle that your dog lives. As your vet knows and has examined your dog, they would have a better answer than someone who hasn't met your dog or knows your lifestyle.
All the best,