As a nutritionist I’d be very concerned about these two diets but they’re different so I’ll differentiate them.
Fruit contains vitamins, fibre, antioxidants and carbohydrates and is really good for you, but it’s missing protein and fat which humans literally can’t survive without, let alone be at least generally healthy.
Also fruit contains sugar which although is natural sugar, would add up to quite a lot over the course of the day if that’s what you were living on.
Too much sugar causes tooth decay (further increased by fruit acids) and stresses the pancreas, leading to diabetes.
Raw vegans eat a larger variety of food, in fact they eat any food regularly vegans eat that doesn’t have to be cooked above 33-48 degrees c.
Other foods can be soaked or sprouted to be made edible too, such as beans and pulses. It’s still a restrictive diet and all vegans should supplement with vitamin B12 which is only found in vitamins, so meals have to be planned carefully to make sure you’re getting everything you need.
The other issue with vegan diets is they tend to very high in fibre and while fibre is healthy, eating too much too soon might be hard to digest. Raw foods are also harder to digest, further increasing the likelihood of digestive trouble, gas and bloating.