mainly treasured tool beset-ing, refines,runes,ninja assists and few others, but i think the difference in power makes it in the fact that the person might had stacked almost everything on his position 1 ninja, and then you have instead of pos1- 20k power, pos2-20k, pos3-20k, pos4-20k he will have like pos1-35k, pos2-15k,pos3-15k, pos4-15k, both of them will have 80k power but one of them will have significant better stats on pos1

as extra, beside initiative, injury is another very very important stat