Voldemort isn't that good a coder - It's a continually updating system, that loads his present mindstate onto the entire system.. And he just rekeyed it to Hermione. All backups and lore: Gone.

Dumbledore loaded the cloak with Bhals stupefication, didn't he? Some delivery mechanism that only tiggered when worn by an adult. Hence the mad cackling and very poor plan for stopping Harry from breaking the universe <,<

Why does he need to create a Horcrux immediately? Theory :

Each horcrux, even with Voldemort's modified ritual, is just a snapshot of Voldemort's mind-state at the instant the horcrux was made. What Voldemort has somehow managed using magic is to interconnect all these Horcruxes into a network, and build some kind of non-biological system to "run" his personality based on the snapshots.

This explains why he was able to observe the stars and think about his mistakes for 8 years until someone touched one of his horcruxes. Somehow, his network sends only the presentMindState to the body it hijacks.

This is how I assumed, previously, that Harry might defeat him. Since magic thinks he's got the same identifiers as Voldemort, is Harry is killed a moment after voldemort is, his mind should become the "top" element in the stack of memory states that is Voldemort's horcrux network. I would assume that he would have access to all of the knowledge in the lower states, but as the top, canonical state, he would have control when Voldemort respawns.

As it is, I'm guessing the respawned Voldemort after he's killed by magical resonance will lack the mind state changes since his last horcrux.

So it looks like some of Harry's magic is on the diary for whatever reason, because Voldemort casting a spell on the diary sets off the resonance hard. Did Harry cast a spell on it earlier?

I think it's very easy and potentially problematic to focus on too-narrow a category for your specialties.

To flagrantly steal an example from SlateStarCodex, examine basketball players. Professional basketball players tend to be tall. Several standard deviations taller than the general population. There is a definite, verifiable link between increased height and increased basketball success.

However, the most successful pro basketball players are not necessarily the tallest. Michael Jordan was not the tallest player in his environment, but was absolutely in the running for being the best. Success in basketball is related to a number of factors, height being only one. General athleticism, spatial awareness, strategic thinking, willingness to train diligently, and so forth are also important. A person who is above average in multiple relevant factors may be a stronger overall player than another person who surpasses him in one factor but falls behind in the rest.

The same is plausibly true in other fields. A person who is two deviations above average in medical skill and two deviations above average in social skills might easily be more successful than a person who is three deviations above average in medical skill and completely average in social skills. The may be more utility in having multiple synergistic skillsets than one exceedingly strong skillset.

Very good.

However, there's nothing odd about his presence with the other children. He's a Slytherin who's been portrayed sympathetically ever since his induction into the Chaos Legion, so it's very plausible that he's a member of the Silvery Slytherins and thus someone Draco would turn to for help in an emergency.

On the first point : he can only be defeated by the Power He Knows Not!