Time is the biggest factor. The second biggest is a writer's block. Cosmic Reach is shifting from working on engine to working on content (a very good thing!) but I don't know how to write a script for this easily...
try making notes about what feature do you want, make it, and when its "done" describe it, if you dont like it, state why in your notes, then repeat until its the feature you liked, if its done, add a final note and compare what you wanted to the result, thats how youll make the next video.
Do not worry if you think the feature in question is boring or irrelevant, itll help you for starting to get videos produced and at least some revenue