Hi Rhedd. As far as balcony goes...it depends on the individual. There are some that think that since you don't stay in your room that much, but are out on the ship most of the time, why bother with a balcony.
I am of the opinion that a balcony is ALWAYS good
As far as which side of the ship, you will have to tender in Belize...I am not sure if they are still tendering in Cozumel so either side of the ship would be good. As far as Bahamas, coming into Nassau, you get a pretty good view when in Port from the right side. And Costa Maya - I have no idea....but after September, I will definitely know.
Hope this helps