There were some scenes where I just thought "oh well, Industrial Light & Magic, we all know you can do it."
but where the special fx didn't really add to the story.
For example the scene in the droid factory where C3PO pulls off all kinds of indiana-jones stunts, hanging off from this floating droid. How ridiculous is that?!
In Episode IV he can't even walk properly in the sand, now he's cliffhanging and doing all kinds of stunts. To me that seemed unneccessary.
Also sometimes it just seemed that there were just too many strange-looking aliens, distracting from the story.
I mean its great to use this technology e.g. for creating a Yoda that can walk and fight and not having to rely on Frank Oz moving a puppet from a hole in the ground. Also I liked the monsters in the arena. But in some scenes I thought, they just overdid it a bit.
Another example: Noticed the computer generated fruit that Anakin and Padme shared? I mean it was cool how he played around with the force (this scene adding a lot to Anakins character: that ist not Jedi-like, "abusing" the force to woe women! Shows his arrogance towards the Jedi codex!) but please, when it comes to eating it, make it a goddamn real fruit! When Padme bites off, everyone could tell, it wasn't a real fruit!