Some consequences:
-Ebla lasts longer and remains a center of autonomous (although Sumerian-influenced) Syrian culture.
-The idea of universal empire (where "universal" means "pan-Mesopotamian") had already a pre-Sargonic basis in the notion of a unitary, abstract concept of royalty for all of Sumer. However, it will crystallize far more slowly without Sargon.
-Sumerian high culture would probably remain even more prestigious than IOTL, esp. if a Sumerian important center stops the Akkadians. Akkadian language will eventually emerge, but in a different a slower way.
-It's damn hard to say what happens to the Sumerian not-really-city-states-anymore. Uruk (renewed) hegemony is likely but the Akkadian regions might be beyond its scope.
- Bottom line, the likeliest outcome is an anticipated structure of multiple regional powers with a somewhat distinct cultural identity like it is seen in the Middle Bronze Age. Tentatively, Subartu, Mari, Ebla, Qatna, some center in the Khabur-Upper Euphrates, Kish/Akkad, Sumer, maybe Eshnunna, Elam, possibly Byblos and Hasor.
- The Amorrean and Gutian invasions will probably happen regardless and act as a factor of fragmentation. However, Sumer might actually be better placed to weather that storm.
-Sumer will be, in the short term at least, less cohesive than it was under the OTL's Ur Empire (I think unification is still likely), but dominance of Middle Mesopotamia is delayed.
- As the Amorreans find an easier time in the Fertile Crsecent, they might not put such a pressure on Egypt. The Middle Kingdom has an easier life.
- Assyria would probably remain Khurrian for time being.