From my experience this simplicity is something you pay the price along the way - development is harder (a good typing gives you a lot of hints about functionality and puts bounds on developers on how to use it) and more error prone (less stuff gets caught by the type checker, instead you find it out in runtime).

Of course it is good to be reasonable - some people completely fly off into the FP world and instead of actually building working stuff they think all day about some clever abstraction and types to model it.