simplify using c to determine what form is considered simplest
Further control of simplification.
In both Simplify and FullSimplify there is always an issue of what counts as the "simplest" form of an expression. You can use the option ComplexityFunction->c to provide a function to determine this. The function will be applied to each candidate form of the expression, and the one that gives the smallest numerical value will be considered simplest.
With its default definition of simplicity, Simplify leaves this unchanged:
This now tries to minimize the number of elements in the expression: