This is the easiest bike to work on I know of. That said, there is always something, the exact something is dependent on your skills.
almost anyone can do the liquid changes, spark plug changes. This is not true for all bikes.
A smaller group can add valve adjustment and brakes. There are many bikes, that require cam shaft removal for this, and that requires a much larger skill set!
A smaller still group can pull the tank and change the fuel filter.
Now beyond this point, there is little if any advantage to the boxer and some disadvantages, like clutch replacement.