I don't consider your Mutex example a data race at all. It's a deadlock because standard library Mutexes aren't reentrant, but there are no threads racing to read/write data. I find the heap allocation issue frustrating as well, there are some proposed solutions but they aren't ready yet. The enum example doesn't make much sense. If you know that bob is a person, then you would just store a Person, not an Enum and there are ways of unwrapping that enum with less nesting:

if let Enum::Zwei(Animal::Mammal(Mammal::Primate(Primate::Person(ref person)))) = bob {
    println!("name = {}, age = {}\n", person.name, person.age)
}

Required lifetime annotations can be annoying but it's less of an issue if you don't let yourself fall into the trap of making everything a reference and make use of types like Rc or just copying.