Yes, absolutely too 'moist' can be a problem. Hooves weren't designed to be waterlogged, but rather for an arid environment. They're meant to be dry & hard.
So in a wet environment, you need to give your horse as much time daily as possible on dry footing. If not, you will likely have to protect soft feet more often & it may be an ongoing battle against opportunistic infection such as thrush/seedy.
In a dry environment, don't stress! That's good! Only thing you may have to worry about is if they're so dry & hard, you may want to soak them for a few hrs before the farrier visits, to make his job easier!
If hooves appear brittle & shelly, then it's likely that diet &/or nutrition is out somewhere. Even if hooves are too 'dry' due to nutrition, painting stuff on has no more bearing on their health than does painting your nails. If the hooves are intact, no splits or such, painting on oils or creams occasionally won't have much of an effect, except to soften the ground surface slightly. If the hooves are split, even with 'microcracks', painting on topicals can just make for a better breeding ground for the anaerobic pathogens. So... save the hoof goop for healthy hooves before a show when you want them to look purdy!