What stereotypes of women are present in The Canterbury Tales?Are female characters oversimplified? Weak? Foolish? Excessively Naive?

Chaucer presents a wide variety of female types.  We have,
for instance, many stories concerning the most beautiful girl around.  The wondrous
beauty can be seen in the Knight's Tale, the Miller's Tale, and the Franklin's Tale.  In
many of the stories we have the young and lustful woman--The Miller's Tale, the Reeve's
Tale, the Merchant's Tale.  In some we have the wise old woman:  The Wife of Bath's
Tale.  In other tales we see women who are virtuous to a fault:  The Man of Law's Tale,
the Physician's Tale, the Franklin's Tale.

Yes, the women
are exaggerations of the women of the time.  These stereotypes serve to enhance the
humor of the work.  Yet, the women are hardly the butt of the humor.  More often the
male characters are the ones who appear more foolish. The women often make the male
characters look foolish.  Allison in The Miller's Tale, for example, cheats on her
husband and gives a would-be suitor her bottom to kiss.  Yet, it is her husband who is
deemed a fool.  In the Reeve's Tale, the miller's wife and daughter unknowingly sleep
with the two clerics, but it is the miller who is knocked over the head by his wife and
the two women have more fun than they ever had.

Patient
Griselda and faithful Constance in the Clerk's  Tale and the Man of Law's Tale are so
virtuous that the men around them are seen as evil.

In
other words, yes the women are stereotypes.  Yes they are naive in some of the stories
and experienced and cunning in others.  Yet, the male characters do not fare any better.
 They are just as naive, foolish, petty, and lustful-perhaps even more so, and they, in
most stories, suffer more for their foibles than the women do for
theirs.