As for Shrek 4, I heard a lot of positive reviews, but there still were some cynical people saying it's a rehash of It's a Wonderful Life (A plot normally saved for Christmas specials, along side the one millionth retelling of a Christmas Carol). As I've said before, I won't have an official opinion until I see any movie, be it Cars 2, Shrek 4, Kung Fu Panda 2, what have ya.
I think rehashing "Wonderful Life" outside of Christmas is at least a twist on that stupid chestnut. Of course, the whole fact of the matter that Rumpelstiltskin actually preventing the day of his birth instead of Shrek wishing he was never born (and rather one day where he was a monster feared by all again) and spending the movie trying to undo it made it a little more interesting than it sounds. Not to mention that all of the first three movies featured Shrek's why me attitude... the twist is, his why me attitude now was that he was so beloved, and questioning it actually caused all the problem. An overall twist to the film series itself. Plus the caustic Puss and Donkey was reduced to 2 one liners in a row, so that' an overall improvement.
The third basically had a "been there, done that" feel the whole way through and it just seemed rushed to theaters with a DTV quality script. But we're lucky... we were gonna have much, much more of these films. Not looking forward to Madagascar 3, and I like Madagascar.
Pixar and Dreamworks (which slowly gained my respect) have done a solid job... some of the other studios feel hit or miss. Blue Sky films seem like they're 3 rewrites short of a final project... Horton hears a Who was uneven... when it was good, it was GOOD, but most of the other times, things didn't mesh. Despicable Me I rather liked, but it could have used a LOT more mad science and a little less family values... I really loved the dark Igor film, but dislike the ending (not enough for me to not recommend it, of course. Steve Buschemi's immortal suicidal rabbit is dementedly brilliant, but only because Steve is the only person who could pull it off). But Sony hasn't made one thing I'd want to watch... not even on a bet, and I'll sooner eat worms than watch those TERRIBLE Happily ne'er After films.
But then again, not all 2-D films were that good... anyone ever see the MGM Tom Sawyer movie? Yeah... you don't have to. You SHOULDN'T. It's an embarrassment.