What are you trying to accomplish with the drivetrain change, better shifting, no front shifting, wider range?
If you just want a better shifting rear, put whatever you like there.
If you are happy with the size of your big chaniring and don't like shifting the front, just don't shift the front; then you will still have a bailout if you find yourself on a steep climb.
I agree that you should plot out whatever gear changes you contemplate to see how it compares to what you have and the gears you use.