Just to start off with some journalistic integrity I have to acknowledge the blatant commercialism that began to seep into Star Wars with the release of this film. Thus far the galaxy had revealed to us all manner of creatuers and characters that were alien. The catina scene in IV alone was a menagare on the visual sense.
Some aliens were terrifying with slimy faces and guttural languages. Others were endearing (Even if they were still a bit intimidating) e.g. "Chewie". But as Ewoks were introduced late into the game it seemed that the primary driving factor behind their design and prominent role in the film was the Toy Factor. You shouldn't be embarrassed if you mistook these frightening forest warriors for teddy bears. Because that's exactly what they looked like. That's exactly what they sounded like. And that's exactly what they were marketed like to all the children watching.