Yeah, I don't treat Engineer as a cascade skill. I can imagine that if I was running a naval ratings campaign, I might care who was a Jump Engineer and who was a Drive Polisher. But that level of specificity just screws the one guy on your team that wants to play Scotty or whoever the latest hotness is in sci fi engineers.
Personally, I also think Sensor Op is a better job class than Navigator. Because the sensor op has stuff to do in space combat and plenty of other situations. Whereas the game has always struggled to make Astrogation do something besides "Save or die".