Christine Hayes, hostile to an inspired view of scriptures, writes:

More important, however, is the existence of sources that hold opposing views of the institution of kingship. Some passages are clearly antimonarchic; others are promonarchic (or at least report neutrally on the selection and installation of Saul as king).

…

Some have argued that while the editors who compiled the text preserved the promonarchic perspective of their sources, they chose to frame the promonarchic passages with their own antimonarchic passages, with the result that the antimonarchic passages provide an interpretive framework and are dominant. The implication is that despite positive contemporary evaluations of Israel’s kings, from the perspective of a later period, the institution of king-ship was considered a disaster for Israel, and that negative assessment is introduced by the Deuteronomistic redactor into the account of the origin of the institution. Others feel that the promonarchic and antimonarchic views were contemporaneous and equally ancient perspectives. Whether one view is older and one later, whether both are ancient or both late— the end result is a complex narrative that includes various views of monarchy in ancient Israel, views that defy easy categorization and that lend the book an air of complexity and sophistication.

A third perspective, one of an inspired scripture and one that only works in the context of Open Theism, is that the conflicting promonarchic passages and antimonarchic passages represents God’s struggles with Israel rejecting God’s Kingship over Israel. Israel has failed God throughout the book of Judges. Every man is doing what is right in their own eyes rather than submitting themselves to God. In God’s preferred system, there is no king except God, but this system has failed due to the people’s rejection of God. This failure is heightened by God’s cycle of blessings and punishments meant to correct Israel and to guide Israel. Israel has rejected all attempts by God to reform them.

The change to a human king represents God’s acceptance of a new strategy, a strategy which is adopted begrudgingly and which has several hiccups throughout the lifespan of this strategy. The entire process shows God’s frustrations in dealing with Israel. God enters the monarchy jaded. This, very well, can explain the conflicting promonarchic and antimonarchic passages within the Bible without need to resort to dual authorship.