Yes, this really bothered me as well. With all the vocal effects at their disposal, Venom could have sounded much more creepy and unearthly in speech patern. If one just watches the animated series from the 90s, Venom sounded "perfect". It makes the villian all the more frightening. It appears that Raimi doesn't really grasp that fact that the alien symbiote is a thinking/ feeling lifeform with it's own thoughts and emotions. That should only be added to Brock's perona in every aspect, including vocal patern. Oh, and Venom should not say something like "I am Venom", but rather, "WE" are Venom"!!
Oddly enough, I don't think the name "Venom" was ever mentioned out loud during the film. That says the "writers" assumed people would know enough about the character to not have him introduced properly. Which also says, they should've known better than to make such odd changes in his character without people noticing; a screech of a roar, everything GG2 did should've/could've been done by Venom to "humiliate" Parker, and the duality of the character.
With that last part in mind, can we really say Rami didn't understand what it would be like for a Symbiote to be "a thinking/feeling lifeform with its own thoughts and emotions" when HE DID THE EXACT SAME THING WITH DOC OCK'S ARMS IN THE PREVIOUS MOVIE!!! (save them talking through their host)
All this said? If there were one thing I'd change about Spider-Man 3, it'd be to hire actual writers. Just like so many others have said on this thread. The story that was written made very little sense considering all the money put into filming it. I really don't want to be one to put the people invovled in this film down, but I'd be willing to bet if you gave a kid a Spider-Man, Venom, Green Goblin, and Sandman action figure, s/he'd come up with a fairly entertaining story. (...maybe that's an exaggeration.)
What still gets me is Sandman turning away from a god-awful, demon looking thing that speaks. Who DOES that?!
One more thing. Peter Parker grew some testicular fortitude between High School and even this point in college. Just like any body else would, ESPECIALLY one who suffered so many life-altering experiences. I mean, I've raised money to pay most of my college tuition all by myself! My swagger was at an all-time high after that. Peter Parker defeated a wrestler, two supervillains (though in the comics he'd done much more), and proved his a** of a boss that he can hang with the pros. But he still acts and cries like a twelve year old?!
I was still getting over "Punch me, I bleed" from Spidey2. When he started sobbing in the park in 3, the entire theater laughed and I wanted to cry myself (not with him, though).
If the writers of the story were changed, the entire film would've been better.