Uranus probably has rings because something collided with it and left debris in orbit, and these debris collected to become the rings. Please read the answer here, where we already explain why some planets have rings.

It is difficult to say exactly what would happen if Venus did not exist. In the shorter term, Venus, along with Jupiter, is one of the major planets that Earth interacts with gravitationally. These gravitational effects cause changes in the Earth's orbit over time periods of tens of thousands of years. Ice ages on Earth result from such changes in Earth's orbit.

If Venus weren't there, we might not have ice ages.

In longer time scales, it's difficult to say.