Sam isn't the problem (even though he kind of is).
Yeah, he kind of is.

As much as I love Sam, he really dropped the ball by having Marko going from a two-bit criminal to becoming Ben's killer. That badly misfired, and that was all his call....no suits involved.
Secondly, I don't know how his brother, Ivan, became involved in the writing process for 3, but it possibly went a little something like this...
http://www.purpleslinky.com/Humor/Satire/How-Ivan-Raimi-Got-to-Write-Spiderman-3.159663Why Sam & Ivan meddled with Sargent and the S3 screenplay is beyond me in light of the success of S2.
Now on the other hand, Sam wasn't the problem with the inclusion of Venom & Gwen Stacy. That was all Avi Arad, and it all became an amalgamation of poop.
Lastly, I habitually attempt to look for the positive in everything, and Spidey 3 is pretty taxing.
Sam's batting 2-for-3, so my trust is still w/ him.
None of the Spiderman movies were good movies. Frankly, none of them were even good COMIC movies (which is measured on a different scale than regular movies).
The first two installments of Spiderman provided everything I enjoy about the franchise in general, they were fun (regardless of some of the creative liberties Sam employed). I will never claim them to be anything other than that. If I want some substance on multiple scales, that's where Buffy comes into play.
I think they should do a reboot in five years and when they get to Vemon they shouldn't be afraid to go for an R rating so they can do him right.
I'll be forging a colony on Mars before a Spiderman movie obtains an "R" rating.

Now after thinking about it for a minute, as a possible villain for 4...this would be outstanding....

But I digress, I just want some more news!