They're probably only changing the connector to make sure you buy new accessories. Rather than buying an old design of dock for little money, you'll have to buy something brand new for lots of money.
It is a bit expensive, but I think (though I might be wrong) its the only one on the market (or at least one of very few alternatives) so it's a complete niche product and that almost justifies it. They will have had to come up with the design from scratch rather than just doing something that's already been done.
If you've already paid £1500-2000 on a MacBook Pro, £400+ on an iPad 2 and £300+ on an iPhone 4S, what's another £150 for an accessory that does something rather useful ?