What's the difference between a generalist and a specialist?  A generalist knows less and less about more and more until eventually he or she knows nothing about everything.  A specialist knows more and more about less and less until eventually he or she knows everything about nothing.  Either taken to its logical conclusion is useless and anyone trying to be both at the same time inevitably self destructs.

The optimum answer is a team of specialists with expertise in the most important areas.

Getting there is possible only if the leader genuinely treasures diversity of strengths.  This is not about diversity on any of the dimensions required by law or moral obligation.  This is about assembling and valuing different talents, knowledge, and skills so the overall team is stronger.