The biggest challenge I feel is to truly make this great product something that literally anyone can use and use well. I think for that to happen we would need to move towards more and more real WYSWYG editing - preferably on the pages / posts themselves.

Clients often still seem to have difficulties with basic WP actions and I still see too may sites with a basic install unedited in any way - for me that shows that often the lay person is still a little intimidated by the backend.