The chronometer is a non-issue for me. I enjoy figuring the target speed out for myself. Besides, in some cases the game gives it to us on a silver platter, as when we get radio sightings that include the target's speed. In other cases we have rough estimates from sonar, and we can refine them by working with the nav map. As for the argument that the current system forces you to be the whole crew, isn't that the fun of a sub sim? It is for me. I regularly man the AA gun, the deck gun, the sonar station, the bridge, the periscope, whatever I like.
For me, the crew-on-deck-injury bug is far more important. And tonight I got bit by the danged A bug; I was trying to surface right after a very satisfying kill, and I hit A instead of S -- before I'd remembered to save my game.