What does Shay's Rebellion suggest about the challenges after the American Revolution that would influence the direction of the U.S. Constitution?

It is true that this rebellion highlighted the need for a
stronger central government.  However, it is even more important to point out that the
rebellion highlighted the need (in the minds of the elite) for less democracy.  One of
the major things that the rebellion suggested was that America was too democratic.  The
Constitution was written (in part) to mitigate the influence that the people could have
on the government.

In the time leading up to Shays's
Rebellion, states were passing all sorts of laws meant to help people (especially
farmers) who were in debt.  These laws were pretty radical at times (mandatory debt
forgiveness, for example) and they scared the elite.  These laws made it very difficult
to build a good economy.  Why, for example, would anyone lend money if the government
might step in and say the money did not need to be paid back?  Without lending, the
economy dies.

The point is that democracy was making the
government do stupid things.  The people were asking the government for things that
would ultimately hurt the country.  Shays's Rebellion turned to violence when
Massachusetts' government would not enact such laws.  That really scared the elite--they
saw the potential for the common people to turn to violence to get short-sighted and
very harmful laws.

Because of this, the elite wrote the new
Constitution.  In it, power was moved away from the people.  It was given to the central
government.  That government was run mostly by people (President, Senate at that time,
Supreme Court) who were not directly elected by the voters.  This shows that a major
point of the Constitution was to reduce the amount of democracy and popular influence on
the government.