A common debate in all media circles, whether the average score should be a 5, or a 7. Usually this falls into two standings, one being it should be objective and that a 5 would be bland, not good enough to recommend, and that a 7 would be the average, the other seeing it subjectively and that 5 should be the average of what you've seen before, and building your other ratings around that. I use something else.
For the most part, I watch shows I enjoy. Therefore, my rating scale reflects that. Why should half or more of a rating scale be used for shows I didn't like? I compress those into 2 ratings, leaving me with 1 neutral rating, and 7 values of which to rank the shows I enjoyed. The cream now rises to the top, instead of being stuck with a hundred other shows with the same rating.
10 - Used for my all time favourite movie and tv show
9 - Amazing
8 - Great
7 - Really good
6 - Good, pretty satisfied with how it ended
5 - Good, ending disappointed me a bit or wasn't engaging enough for me to be hungering for the next episode
4 - Not bad show, probably a bit boring in parts, but had good moments
3 - Neutral
2 - Was not interesting or engaging
1 - I did not like it
Comparing my rating distribution to the global average, you can see that both have 40% of the scale containing only 10% of the total scores (1-4 on the global, and 7-10 on mine). The advantage with mine is that I use my less frequent scores for shows of high enjoyment and quality rather than of high disappointment and garbage. I essentially reserve 10 for my most favourite tv show and movie, when really it's practically on the same level as a show rated a 9 because I have the room to do so without crowding my other scores. Now, I can easily decide what to rate a show and be confident it belongs there.