Can someone explain me why Alistar heal not giving assist but Soraka and other champs give assist ?

janna's ult doesn't give assist for healing either. Nor does sona passive aoe aora. It has to intentional interact with someone not just hey i was around. OR people with ageis would get free assist left and right

It should, if it doesn't then this is a bug report and not a live balance suggestion.

I just started playing Alistar more often, but haven't noticed it. Are you sure it isn't just a bug?

I have had Soraka ults not give me assists lately. I think there is a bug when it comes to healing/assists in general.