Graham Onions and Charles Shreck playing for England... as if we're not already the laughing-stock of World cricket...
Seriously, there's a reason we keep chopping-and-changing in ODIs - it's because if you pick someone and they go for 5.5-an-over repeatedly, to continue to pick them is what's known as innate stupidity. If you try someone and they don't do well, you drop them. Anyone seriously expecting Liam Plunkett to amount to much is expecting one hell of a lot. It's not as simple as "pick X and stick with him". You can't just turn a crap bowler into a good one by showing faith in him. The reason New Zealand, Australia and South Africa have high-quality seam attacks is because they have lots of good bowlers, not because the selection is exceptional. If England pick Plunkett and Broad right now the likely outcome is lots of very, very high totals against us. Because these 2 bowlers are not very good. And knowing your teammates well won't help you bowl well - only one person can bowl the ball at a time. It's up to the bowler with the ball in his hand, no-one else can do a thing at that time.
Nor is it as simple as Anderson being given the new-ball. The new-ball only lasts 20 overs or so. Sure, Anderson might (and only might - the new ball is a privelidge, not something to be thrown around randomly) do better with the new-ball, but you can't just look at simple stats like "when he's opened he's got X, when he hasn't he's got Z". The only way to do it is to look at opening spells - and the only time Anderson ever opened the bowling for England was in his first series against South Africa, where he was mostly very far from exceptional. Right now, there are several bowlers I'd prefer give the new-ball to, though Harmison isn't one of them. How on Earth he ever got near the new-ball is beyond me, he's never, ever used it well and rarely ever takes even a single wicket in his new-ball spells.
There's nothing wrong, BTW, with the captain talking to the bowler. Sometimes bowlers are failing to do something which is not remotely difficult to try to do - and it's generally a good idea for a captain to see if he can help (ie ascertain that the bowler is trying to do what he should be and getting it wrong rather than trying the wrong thing) rather than let the bowler continue to get the treatment.