Two points. First, we need to make sure the facts are correct. The fact being that 1 J-11 beat 2 Thunders after several rounds of combat. It would be most kind of you if you could update your comment to reflect this.
Next, we should not let personal biases come in the way of analyzing facts. You may think that J-11B is better designed, but unless you can present solid evidence, it is only an opinion.
For the record, I believe that Thunder is better designed for the following reasons:
1. Smaller size leads to reduced RCS.
2. Smaller size means that for the same speed and same maneuver, the Thunder pilot experience lower Gs than Flanker.
3. In Thunder, Russian inputs have been used to reduce heat and noise signatures.
4. The AEWAC + Thunder combination improves the stealthy aspect.