Nice chap.
One more thing to ponder - it's said that you-know-who is the most feared and the most powerful dark lord of the last century... Why exactly? Voldemort is just a terrorist with not so big group of followers. I'd think Grindewald who was Hitler's companion would be much more feared - it's not like Voldemort has killed several millions of people, right?
And why exactly all muglleborns fear his name also? Being muggleborns they should have more common sence.
About Hogwarts:
A bunch of children. Near the lake. Completely unsuperwised. WTF? O_O
And more:
Just how large is Hogwarts' staff? I've counted about 13 including Binns, Dumbledore and Filch.
Now what about students? Let's consider Harry's year is average. 21 students. 147 for seven years. Just 7 more than there are staircases in the castle. And how 13 people are going to have any idea what are other 147 doing in this huge castle?
The student's population raises another concern. How much people does British wizarding world have? let's say average wizard/witch lives about 120 years. Then there should be about 2500 people - if Hogwarts is really the only one British school. 2500 people can't form economically independant and stable society.
This is not plot hole or plot crater :) This is f...g plot void.