Arguments for and against the Norman theory?

The Norman theory is supported by the following facts:

1) An ancient chronicle, which says that in 862 Rurik came to Novgorod, who seized power;

2) On the territory of the northern lands, archaeological artifacts are found that belong to the Varangians.

This theory is refuted by such factors:

1) At that time, large cities existed on the territory of the Eastern Slavs and trade was developed. Thus, there was a tribal nobility. This suggests that statehood could have arisen before the arrival of the Varangians.

2) Rurik only seized power as a result of the feudal struggle, and did not establish statehood.