Hi Belen - Those are really good points. When I was doing research for this article I had some deep discussions with the other Instructional Designers on my team because I was trying to find out... if you add one or two of these techniques to your course, does that mean you've "gamified" your e-learning? How many techniques do you need to include to have gamification? There's no solid answer to that.
I also think it's important to investigate and understand the differences between game-based learning and gamification. They are 2 different things and serve different purposes. I think you can apply gamification techniques to a course without making it a true "game". I think thats more the purpose behind game-based learning. Just an interesting thought...