I think we should see it from Neville's eyes, not Snape's. Snape's motivation is already explained in his actions, but I'd like to know why Neville has had a change of heart about Snape.
Author's response
That would definitely be an interesting alternative take on this story! You'd be welcome to write that point of view if that's the story you wanted to read instead of mine. Snape's POV is the one I tend to be interested in so my fiction tends to be Snape-oriented. Thanks for your feedback!