People have differing views... While a lot of manufacturers or dry food suggest that that's all they need there is a lot of research to suggest that cats benefit greatly from a diet that is reflective of what they would eat in the wild so suggest a wet diet. Cats who only eat dry become addicted to it as it's covered in a nice tasty (but unhealthy) coating which they love. They are also more prone to urinary tract problems as they don't get enough moisture as cats don't tend to drink all that much. They would get lots of moisture from wet food. dry food is also full of cereals which are not exactly helping cats to live the carnivore lifestyle they are made for. So is some wet food so trry to get one with a high meat content.
Personally, I feed a predominatly wet food diet with a few dry biccies in between to graze on as a treat. I have one cat though who has a dry prescription diet because she has urinary tract problems from being fed just a high phospherous, dry diet when she was a kitten before I had her, as consequence she can get very poorly if she every eats any other food elsewhere and is also addicted to dry food and won't touch wet (dispite my efforts!).
Cats who feed only on dry can also get weight problems if owners are not careful to measure out how much food they should actually be having- the daily amount of dry food advisable is deceptively small where as a lot of owners just fill the bowl up an the cat ends up with four times as much food as they should!
Maybe you could try feeding a mixture of wet and dry? Cats enjoy a variety anyway.