I was an enlisted nuke before going to college and getting an engineering degree. Even in the early '00s, my impression of the nuclear program manager role was very similar to yours, in that the naval officers are primarily providing oversight rather than design engineering work. However, there is still quite a bit of original work going on in the nuclear Navy. In the late 80's, you might have been involved in the Seawolf class design.

Each new ship class has been getting a new reactor plant design. The changes are very much evolutionary from one generation to the next, but it all adds up.