Managing Battery Temperature is an issue with all traction batteries in all cars and with all chemistries. I would only assume that Leaf was designed to be an urban short-distance type vehicle
I just watched the documentary, 'the revenge of the electric car'. Thats exactly what the CEO of Nissan said, he said they don't care about range anxiety, they are targeting the urban user.
You can take your Leaf on a long trip with lots of charging hops but that is not what its designed for.