"So she named him Joseph, saying, "May the Lord grant me yet another son."Genesis 30:24.
Rashi says the name alludes to a prophecy seen by Rachel that Jacob would only produce 12 tribes. So she prayed that the one after Joseph would come from her. However what is peculiar to me is that when Leah bore her children she named them names that had to do with them. Each name was directly correlated to the experience of having that child, ie very individualized. Reuben is a conjunction of the hebrew of "seeing" and the hebrew word for "son". Thus alluding to Hashem seeing her affliction and remedying it with a son. Judah has to do with giving thanks for Judah being the fourth child which connotes abundance. But Rachel has Joseph, her first child ever!, and then just asks for another. It makes it seem that Joseph was just a means to an end or a segue but nothing else. And apparently Joseph is pretty important in the Torah!
There must be something more here.
Why is this? Is there any literature on this peculiarity?