we won’t really know him, unless you let us inside.
You show the inner world of your character by telling the reader his thoughts, emotions, attitudes, fears, longings, neuroses, drives and compulsions. There are two kinds of thought your character has: (1) thoughts about events that have occurred and (2) peripheral thoughts.
Omniscient is the all-knowing narration, mentioning what this or that character is thinking or feeling any time the author pleases. Characters are kept at an arm-length and equal. The reader finds it harder to identify with one character and to get involved. Thankfully we have many viewpoints to choose from. Readers can live the adventures along with the characters by hitching a ride on their shoulder or even from within their minds.