I would say a large amount of soldiers are heroes whether they die or not, based on the fact that they were brave enough to go through with such a dangerous profession that many would never think of doing. Then there are times where a soldier may jump on a grenade to protect the lives of other people or other such cases.
They are not any more heroes than anyone else dying on their job, unless they actually died doing some heroic feat. most are just victims of the war, not heroes. Soldiers are not soldier to sacrifice themselves in order to protect their country or whatever the army fight for, they are because the army offered them a career - while they might believe in what they fight for, they are in it predominantly for themselves.