"Trust but verify" VNAV is only as good as the data it can work with. It does a decent job but you still have to monitor it.
High on profile with no speed constraints by ATC? Increase you airspeed is the most efficient method. Fly the airplane first, then update the VNAV descent page with the increased descent speed.
Landing gear is your friend if you have too much energy in close and need to reduce your energy state.
