It seems as if the people of Joseph were very strong in numbers. Having lots of children was considered a blessing from God (see Psalm 127:1–5) which is also how the people of Joseph seem to have understood it. The reason why they asked for a larger portion of land is not clear. Certainly they were not shortchanged—their combined territory being larger than that of any other tribe except maybe for Judah's. Their discontentment, similar to the spies (Numbers 13:26–33) and in contrast with the humility of Caleb (Joshua 14:6–12) and the daughters of Zelophedad (Joshua 17:4), shows that they actually questioned and challenged God’s wisdom and goodness.1
14 Les fils de Joseph parlèrent à Josué, et dirent: Pourquoi nous as-tu donné en héritage un seul lot, une seule part, tandis que nous formons un peuple nombreux et que l'Eternel nous a bénis jusqu'à présent?