In the pisode of Cosmos dedicated, among others, to cometary objects, the Oort cloud was graphically rendered as, as its name suggests,  a spherical distribution of dots.

This surprised me as I thought that it should be somehow a disk or a torus, given the solar system rotational momentum. 

Why is the Oort ensemble thought to be spherical? It is deduced from the orbits of the various comets? I think so.

How is possibly explained that it does not spread to a more disk like object?