The failure of the Book of Shoftim to mention any flaws concerning the first four judges - Otniel, Ehud, Shamgar and Devorah - should be taken as an approval of their reign.
There is only one single subject that is discussed in the Song at the Sea, and that is God's saving might. Devorah's Song, on the other hand, while certainly neither negating God's intervention nor downplaying it, nevertheless acknowledges the role of numerous human characters in the victory. At the same time, Devorah discusses the complex and divisive dynamic that was at work among the tribes of Israel, as some of them selflessly volunteered for what must have seemed a lost cause, while others, who were geographically beyond the direct threat of Yavin and Sisera's tyranny, remained aloof and seemingly unconcerned.