I've never used an integrated visor helmet, but want to.
You could try using ones already on the market to see what you like about them and don't like. Even ask some shops that have them on what feedback they are getting and read some reviews. The immediate issue is..
- is there space for a person to wear specs under the visor. That's a big market to address, people who just want to wear their prescription glasses under the visor, so even a tinted visor would be great, and the inside of the helmet should have room for the glasses to fit without being squashed. Maybe when a person buys a helmet they can get a clear visor, with the option to buy or swap with a tinted visor.
Also, how do you prevent fog? Perhaps the visor can have space at the nose for air to leave, like a face mask, but still protects the nose from wind.
Also when you take off the visor, there should be a hook at the rear of the helmet to hold the goggle strap.
Also, a way to insert speaker headphones would be interesting. Perhaps you can suggest some headphones for people to buy that can be inserted next to the ear.. ie you'd just want the speaker part, not the headwrap. That said, headphones can be dangerous when you can't hear people calling out at you for whatever reason.
the helmet should actually work too, and the visor whatever the tint should be of good quality, blocking all relevant parts of spectrum.
also, an inbuilt gopro mount would be cool