Concerning the Luna episode, my theory is that, while ponies do recognise that she is back to being plain old Princess Luna, they are still a bit apprehensive about welcoming her so soon. After all, she did try to plunge their world into eternal darkness. I doubt that they'd really be quick to forgive it.
Also, havig finally met some other bronies in person, I met one who's currently working on a comic about the origins of Celestia, Luna, and Equestria as a whole. From what he's told me about it it's gonna be pretty awesome. It's chock full of verywell thought out in-universe theories on such things as why she is called Princess Celestia when she is clearly a queen, and why so many things in Equestria seem designed for human use rather than pony use. I don't want to give away anymore to publicly, but if youwant to hear more in detail, give me a PM.
Also, in other news, I now have ordered a Derpy Hooves shirt. My conversion to brony is complete.