Hello Cough
Thanks for your thoughts.
Regarding your questions: I cannot think of a situation in which VNAV will change to VS in this phase of flight other than by a button being pushed, but then I'm sure someone will be along to point out what I'm forgetting in a minute? If, on the other hand, ATC were to give us a heading VNAV would obviously decouple on selection of HDG and the verticle profile would lapse into pitch mode. At which point you're no longer on the stepped-climb departure anyhow, and anyway ATC will always give you an altitude cleared to, in such a case, which will prompt you to reset the altitude preselected if necessary.
No, I wouldn't use VNAV on a single-engine climb, because when in an emergency I'd advise ATC and be allowed to fly whatever profile I'd have to in order to put the aircraft on the ground safely. In other words, I'd be off of the usual stepped climb SID and under vectors as an emergency aircraft, concentrating on reaching whatever acceleration altitude applies.
Passenger comfort is very high up on our list. (and believe me they wouldn't hold back!) No complaints from them about VNAV, ever. Works well, at least on our airframe.
Are you saying that you prefer not to use VNAV at all?