When you make these almost spherical it is difficult to see what works when on the lathe, I find. I usually take them off before starting the hollowing and have a look at them for a while. Still get it wrong though sometimes LOL. Whilst I agree basically with Les and Bryan at the end of the day it is a matter of design and personal preference. I would rather see the curve at the base disappearing more gradually than you have done but not sure about having a step at the top.
Pete