Content quality
Learning goal alignment
Feedback
Adaptation
Motivation
Presentation design
Interactivity usability
Accessibility
Reusability
Standards compliance
REFERENCE
Leacock T.L. and Nesbitt J.C. (2007) A framework for evaluating the quality of multimedia resources. Education Technology and Society 10(2) 44-59
This in 'Evaluation of e–learning materials. A holistic framework'. Bundsgaard and Hansen (2011) Vol 4. No. 4 Journal of Learning Design. Which is worth looking at in itself (I'll come back to it I am sure).