Soldiers who were executed for offenses during World War I should not be pardoned for their actions. Those soldiers that committed those acts did those on their own accord, and if they were bad enough to where they were executed, they need to keep that with them, not have it pardoned.
Those soldiers who are involved in war crimes should not be pardoned because of the duration of their stay. That would mean that every long term prisoner would think that they could get release based on longevity or the advancement of age. An offense in WWI should not get pardoned.