Well, I'd hope that Harry saying that, and admitting that he himself was initially going to be Slytherin, would have the effect of making his son feel less afraid of being Sorted there. But yeah, it's pretty weak and I can definitely see how it reads as lip service.

I think that's one thing that upsets me about Snape dying, is that we then never have to see Harry actually adjust and deal with the man. It's pretty easy for Harry to just say "oh, I was wrong" and give his son that middle name, but having to actually negotiate his relationship with the living person would have been much more interesting and meaningful IMO. Not to mention that while I'm glad Draco and the Trio don't seem to utterly loathe each other anymore, they still remain separated by that gulf of blood status and Houses.

I suppose to be fair, changing those sorts of deeply ingrained attitudes and practices is going to be long, involved and difficult. Heck, the Wizarding world hasn't even seemed to grasp doing something like having mandatory Muggle studies that can teach them what Muggle life and society is really like (something that's sorely needed, if the attitudes and knowledge level of even "nice" wizards like Arthur is any indication). So I think all this book really feels like is maybe the barest beginning down that road.

Which is possibly more realistic, that things wouldn't change all that much, but personally a greater change would have felt more dramatically satisfying.