Reuven can be broken up into
two Hebrew words: re'u
(see) - HaShem saw her affliction; and ben
(son), the result of this "seeing" HaShem granted her a son.
The Midrash states the name Reuven is a prophecy related to the future redemption of the Benei Yisrael, in reference to the passage, "I have surely seen the affliction of My people" (Shemot 3:7)
Encampment position - South
Dew and rains of blessing emanate from the south - blessings come to the world in the merit of teshuvah.
After the incident with Bilha, Reuven confessed his error and repented. Reuven, the first great baal teshuvah, implanted the potential for teshuvah in his descendants.