Raeder shaped the Kriegsmarine by removing rival talent

Were the Kriegsmarine's senior officers weaker than those of Germany's earlier navies?

Yes; Raeder's effort to impose his preferred navy drove out much of the available senior talent.

The Kaiserliche Marine and Reichsmarine fielded stronger admirals than the later Kriegsmarine. Raeder removed many capable officers while reshaping the service around his preferred model. That narrowing left Dönitz and a limited group of alternatives near the top when wartime leadership was required. The answer turns leadership quality into an institutional succession problem, not simply a comparison of individual personalities.