In the middle of the frequency dial a button that says 'LOCK'
could be added to lock the transceiver at the chosen frequency.
There are quite a few times the operator accidently hits the
left or right arrow key moving them off frequency. Also the
sight impaired would be helped using such a button.
Yes that would be very useful however I don't think that the CQ100 programme is undergoing much in the way of development at the moment.
In our little group on 14.184 three of us have inadvertabtly done this in the last couple of months in the middle of an over, and after a while discovered that we were transmitting on an adjacent frequency. Everyone else in the group wondering where we had suddenly gone.
Other useful features would include the ability to resize and minimise both the CQ100 transciever and the QSO tv. Even at relatively high resolutions they take up far too much space on the screen.