Is weight management vital to good health?

Absolutely! Aside from quitting smoking, it's one the more important thing you can do to improve your overall health.
YES. Weight management is absolutely, positively vital to good health. Despite what you may see on tv, there is no such thing as a "health but overweight" person. They might not have one foot in the grave but they are not healthy (or at least not as healthy as they could be). And even if bp, labs are normal now, given time these will become abnormal and effect overall health status.
Carrying weight. Carrying extra weight puts demand on the whole system. Fat tissue is living tissue, so the heart and lungs have to work harder to supply the extra tissue with oxygen and nutrients, and the muscle and joints experience more stress to move around the extra weight. The liver is a place where fat is stored, and the fat can push on the surrounding liver cells and effect the liver's function.