As MrsKCastle says, the most important thing you need to know is whether or not this is an ICS appeal as that has a huge bearing on your chances of winning the case. If it is an ICS case none of the points you make in your post will help. Indeed, even if it is not an ICS case they don't make for a strong appeal. Assuming this is not an ICS case:
he is happy and excitedly waiting to start to reception
In the absence of expert evidence to the contrary the appeal panel is likely to think he will settle quickly regardless of where he goes to Reception.
He has asthma and was using current school after school activities
Any school should be able to cope with asthma so that is unlikely to help. The after school activities may help but only if the allocated school doesn't have anything equivalent and you can show that your son will be disadvantaged as a result.
some behavioural concern
Again, any school should be able to cope with behavioural issues.
I am a parent of my preference school nearly 11 years. This changes also effect me.
I'm afraid that isn't relevant for appeal at all. You could be a governor of the school and it still wouldn't help.
If this is not an ICS case you will need to produce evidence that your son will be disadvantaged in some way unless he attends this school. If this is an ICS case you should only be able to win if the admissions process has gone wrong in some way that has cost your son a place.