Of course, it became apparent to me very quickly that he [Harry] had no extraordinary talent at all. He has fought his way out of a number of tight corners by a simple combination of sheer luck and more talented friends. He is mediocre to the last degree, though as obnoxious and self-satisfied as was his father before him. (emphasis mine)
That's an odd thing for someone to say if he's NOT loyal to Dumbledore. We have been told by several people that Harry has the makings of a very powerful wizard, even though his grades in school may be less than desired. He is, for example, very skilled at DADA. We know he has conjured up a Patronus, which we are told on several occasions is a very difficult thing to do, and not something that dumb luck would help him with.
It's in the Order of the Phoenix's best interests for the Death Eaters to think that Harry is incompetent and the beneficiary of good friends and dumb luck, because then they might take him less seriously than they ought.
I'm taking my sweet time on this re-read of HBP, and then (hopefully before GOF comes out this fall) I'll tackle the entire series again. This is FUN!
In short, let's lull the DE's into a false sense of security
Then.......WHAM!
Harry will hit 'em hard!
Except I truly believe that Snape doesn't like Harry because of his history with James. Harry is just like James was as far as getting away with things (he's not as mean-spirited though) and I think that grates on Snape, plus the fact that Harry looks just like James. Snape will teach Harry, he will try and give him the skills he'll need to face Voldemort and the DEs but I don't think he likes him at all.
Hmmm...that's a good point, and one that I missed. I am really going much more slowly with this re-reading. I hope that will help! :)
Good point! Keep an eye on Wormtail, too... Snape mentioned that he has taken to listening at keyholes... on Voldemorts orders, perhaps? Voldemort doesn't trust Snape near as much as he thinks?