What if Clovis failed to conquer Gaul from the Gallo-Romans, preventing his conquest of the Alemanni and the Visigoths in Aquitaine?
This would leave the Franks probably divided, pagan, and inhabiting the substantially "barbarized" former Roman frontier. While the Franks were Romanized militarily, without significant Gallo-Roman elites to ally with there's little reason to convert to Chalcedonian Christianity in the short and medium term.
In terms of laws, the Franks did not leave the existing Roman administration in place, or at least the extent to which they maintained them was far less than the Visigoths or Burgundians. If the Franks remained pagan or later converted to Arianism, Frankish structures would be significantly more "barbarian" in origin.
How would the kingdoms of the Visigoths, Burgundians, and of Syagrius develop with a much restricted Frankish kingdom? I would assume that the Visigoths thrive much more if they retained their core territory in Aquitaine.
The Saxons and Bretons of Armorica could be significant power brokers in the Kingdom of Syagrius. Moreover, the Gallo-Roman kingdom doesn't seem like it would be long lived. Who conquers it without the expansions of Clovis?
The Frankish conquests were prone to regionalism until the consolidation of the Carolingian era. By contrast, the Visigothic Kingdom and Ostrogothic Kingdoms appear to have had a more centralized nature. Would divisions such as that between Neustria and Austrasia still appear?