I feel critical thinking can be taught but it really depends on the student and what their goals are.

E learning requires the instructor to spend more time to prepare than with traditional learning.  Promoting participation in asynchronous discussions is important for critical course information.  it is useful to have so many ways to improve on this.  

Knowing a students learning sltyle or styles can help the instructor when it comes to participation. Strategies such as small group projects can help those learners with low participation.  

Establishing an online presence is a major factor when it comes to e learning.  A quick trunaround time is needed for students to feel supported.  Clear communication is key with e learning.  

There are many advantages that come with online learning.  if yotu are open to new techniques of information exchange then e learning can be very successful.  It is priority to have both the instructor and the learner fammiliar with the CMS inorder to have a positive experience.  Failure of this working knowledge in the begining will ultimaltly affect the whole learning process.