The definitive character rankings (in terms of character and acting) are as follows:
1. Hound
2. Olenna
3. Bronn
4. Tyrian
5. Ned
6. Roose Bolton (best villain actor)
7. Tywin (#2 villain actor)
8. Margaery
9. Joffrey
10. Stannis
11. Varys
12. Cersei
13. Daenerys
14. Davos
15. Catelyn
16. Robb
17. Arya
18. Sansa
19. Ramsay
20. Jaime
21. Theon
22. Jon Snow
23. Bran
24. Sam
25. Brienne
Although Jon is the worst main character, he's still better than Bran, Sam, or Brienne. These are the official rankings and, while you are free to disagree with them, just know that you are wrong and your opinion is very stupid.