Is my son still a not mild case of autism

My son has been diagnosed with Autism when he was four and half years old after one year of long wait. Now he is five and half. When he was diagnosed, we were told he is not mild but very bright.
For the past five months, he is progressing really well.
He is very social at school. He is doing great both socially and academically. He loves to have friend around. We can drop himself off to birthday dinner or parties with no problem. He loves all sports, and he is pretty flexible in term of schedules. He loves to bargain. He has all the abilities and characters of a typical child, but he also has other characters.
He has trouble dealing with his fears. He told me that he is only scared of buttons and dummies now. But he refuses to take airplane because it hurts his ears. He will throw tantrums prior departing. He will refuse to go to school because a kid pouched him. When there is fear, a lot of anxieties. His behaviour therapist told us kids with aspergers normally have high anxieties.
He copies moves and talks from video games, and wants us to play with him as per video games. He builds Olympic podium and others staffs he watched from WII games using his blocks.
When he is tense or excited, he became less aware of environment. He got excited and loud at doctor’s office. He will be silly, and acting out to be the center of attention, so everyone will look at him.
He is very easily to get excited.

We often wonder about the diagnose because everyone has been telling me how well he is doing, and we feel he is doing fantastic jobs. We wonder why he is not mild. Of course, he might change since one year ago.

He is receiving about 20 hours per month behaviour therapy and he is on vitamin Bs prescribed by naturopathy.