I believe that Chuck Hagel has an advantage for having direct combat experience. He can have direct empathy and understanding for what a troop on the ground goes through on a day to day basis. As a result, he can make decisions based on the direct impacts on people's lives because he understands this aspect of how the military works.
From what I have read Hagel's war experience was in the Vietnam War era and his opinions about war were strongly affected by that. There is speculation that he might radically change attitudes towards military involvement in other countries because of his beliefs, and if so it would be an advantage to our country to have a fresh look at the direction our country has been going in for some time.
Hagel's combat experience happened a long time ago. There's no way we could know how it would affect his position. It is simply an aspect of his life. He is at a disadvantage, though, with his lack of budget experience. We can't know what the combination of these factors will bring.
It's been a long, long time since Hagel saw combat or had anything to with combat decisions. Others who have had combat experience have had views that differed widely when they actually were assigned to similar positions. Hagel's views as a whole are what matters, not the least of which is his position on Israel.