Yeah, I totally agree. Snape being genuinely evil would have been extremely problematic, after the way Harry's erroneous suspicions have been proven wrong in book one. Dumbledore is fallible - the main argument for Snape being truly evil was his quote about being smarter than most men and thus making bigger mistakes, as I recall - but this would've made him a complete fool, and we can't have that. Besides, it would've been way too obvious, what with the scene with Narcissa and Bellatrix, and then later the one with Draco. If he really had been evil, we'd have had more conflicting evidence so that his turning out to be evil would have come as a shock.

It's interesting when you think about it. Regulus is sort of like Malfoy, but even his own brother thinks he's an unrepentant Death Eater. And Regulus makes me think of Karkarov, which makes me wonder why the Order didn't offer him protection in return for information. Or perhaps in return for nothing - Snape already provided the information, after all.

Impressive that Regulus figured out, all on his own, what as far as we know nobody else except Dumbledore - much later - figured out.

Yeah, this is definitely a bit of a wrapping up of the series so far - the years in Hogwarts - and a sneak peek ahead into what the next book will be. And some rather dark stuff there: "He could not let anybody else stand between him and Voldemort; he must abandon for ever the illusion he ought to have lost at the age of one: that the shelter of a parent's arms meant that nothing could hurt him". Particularly that "ought to have lost at the age of one". For the hero of a YA fantasy series, Harry is really quite dark in some ways.