As a child development specialist what do you think are the pros and cons of categorizing children into three basic temperaments (easy...

The pros and
cons of categorizing children into three general types of temperament both have to do with the
fact that there can be a great deal of variation within each temperament.  That is, not all
children who are categorized as easy (for example) are identical to one another.  This brings
about both pros and cons.

The major pro is the fact that categorizing
children makes it easier for us to understand them to some degree.  As mentioned above, there is
a great deal of variation within each temperament and each child is different.  Categorizing
children allows us to have some hope of understanding them better without having to study every
aspect of their personality.  We can simply look at a child and say that they are easy or slow
to warm up instead of having to try to understand every facet of their personality. 
Categorization, then, saves us the time and trouble of having to study each child in great
detail. 

But this is also the problem with categorizing children.  When we
categorize them, we overlook the differences between them.  If we have, for example, three
children that are all generally categorized as easy, we might treat them all in the same way. 
This may be less than ideal because the children may be different in important ways.  By
categorizing them, we gloss over these differences.  When this happens, we do not treat the
children in the optimal way.

With regard to individualist and collectivist
societies, it is hard to be objective since we (I am American) are members of what is often said
to be the most individualistic society on earth.  Therefore, individualism seems normal to
most Americans and collectivism will often seem to be disadvantageous.

I
would say that individualism is good because it teaches children to be independent and
self-reliant.  This allows them to take care of themselves in a variety of situations.  On the
other hand, individualism can make children more self-centered than they otherwise would be.  It
can teach them not to care as much about others as would be ideal.  I would say that
collectivism has the opposite advantages and disadvantages.  It encourages children to care
about others, but it can also make them less able to do things for
themselves.