The earth is an ellipsoid, because it spins. The correct term is a "spheroid", which is a sphere that has been squashed slightly. The non-uniform gravitational field that a spheroidal Earth has causes satellites orbits to precess around the Earth's polar axis. The Sun is also a spheroid, and the orbits of the planets precess for this reason. Hot and cold periods in Earth's prehistoric climate have been blamed on the precession of Earth's orbit, causing summer in the northern hemisphere to coincide with the perihelion, or closest approach to the sun on Earth's elliptical orbit, roughly every 22,000 years.

So if stars are spheroidal because the rotate, and some stars detonate in a supernova, creating a black hole, and that black hole grows and envelops the universe, then perhaps we should expect the universe to have a residual flattening, at least at the scale it had grown to when recombination occurred and the microwave pulse was given off.