It's not the smallest paradox of diminishing returns that the first POTC film was based on a theme park ride and was huge fun, while the fourth one is "suggested" by a damn good book and is more or less pointless. Sadly the producers haven't noticed this, and the movie ends on a promise of endless sequels, with Johnny Depp's Jack Sparrow practically shrugging at the audience while explaining to his bosun that it looks like he's stuck being a pirate forever.
It's pointless asking them not to make any more sequels, but I could at least dream that they won't make the next movie in 3D. As usual, the 3D is a huge waste of time. The technical constraints in setting up a 3D shot tend to flatten out action scenes perversely, and the payoff is usually something getting pointed out of the screen and nothing more. So you get an overall muddy and washed out look because of the polarising filters, and action scenes which are closed in, murky and lacking in real movement. This is a shame because even when the other three movies stopped making sense (the first one succeeded, I think, because making sense wasn't even on the list of things it was trying to do) the action scenes had a brisk imagination to them. The better ones were almost as good as Jackie Chan, and a lot of the best physical fun in the movies came from the way that Depp could be simultaneously agile and clumsy.
The real fun, and the real reason why Depp is trapped on this hamster wheel (and there's a hamster wheel sword fight in one of the other movies which outshines anything on the action side in the fourth movie), is Jack Sparrow. They wrote out (and flat out killed) most of the big names by the end of the third movie, but Jack Sparrow was box office magic. Depp is one of the few actors who'll drag me out to look at anything on spec - even though I didn't think that The Touristwas any good, the one thing which was worth watching was Johnny Depp. I honestly think that you'd get the POTC film everyone wants if you just put the camera on Depp for a few hours and didn't bother spending any money on stunts at all.
And it's not as though they stopped with Depp. Geoffrey Rush is back, chewing the scenery as Captain Barbosa. Which I can honestly take or leave, especially the Cornish accent. Penelope Cruz is there as well, trying gamely to smoulder as much as Johnny Depp, and inevitably failing. But I've saved the best for last; Ian McShane is Blackbeard. Damn, that's all they needed, really. They could have shot the film as Waiting for Godot with Depp and McShane sitting on whatever the pirate equivalent of a park bench is, just doing Sparrow meets Blackbeard, and made as much money as Avatar did. During the third POTC movie they unaccountably hired Chow Yun Fat to play a pirate and then gave him next to nothing to do. Giving Chow Yun Fat nothing to do in an action movie is - I actually can't think of an analogy. My sliding scale of stupid things doesn't run quite far enough at the stupid end to cover it. Anyhow, I thought they were going to make the same mistake with McShane when we'd got through damn nearly an hour with no sign of him. He's still not in enough scenes, but he makes the most of all of them. Sadly he dies at the end, but as POTC watchers know, merely dying is hardly an obstacle to being in the next sequel. I hope they bring him back.
Things I hope they don't bring back; the whole subplot with the mermaids and the priest lashed to the mast of the Queen Anne's Revenge. I'm quite hoping that those two plot points got a happy ending at the end of the movie there because I really don't want them getting in the way of what POTC ought to be about, which is Jack Sparrow being awesome and everyone else trying to keep up. Anything else is just a waste of everyone's time.
So, that's the recipe for five and six. All Depp, all the time, bring back Blackbeard, and don't bother with the action scenes, they just get in the way. And you can bring back Penelope Cruz, I suppose.