Was the Warren Court's decision in Terry v. Ohio a good idea or did it grant the police too many powers and create a precedent dangerous to the...

I would argue that the Warren Court's decision did not
create a precedent that was dangerous to the 4th
Amendment.

Chief Justice Warren's rationale for the
decision was that the police need to investigate suspicious activity.  Activity that
might lead to a crime will not necessarily be obvious enough to give probable cause, but
such activity still needs to be investigated for the sake of the public's right to
safety.  When the police (who have a very dangerous job) investigate such activity, they
need to be able to ascertain that the person they are contacting will not be able to
harm them.  Therefore, in Terry, they are given the right to frisk
the individual for
weapons.

The holding in this case is not
dangerous to the 4th Amendment.  Instead, it is a valid way to ensure the safety of
police officers who are acting in ways that are consistent with the Constitution and
with public safety.