According to the leaks we've seen, it's thought that the next iPhone (and maybe all future Apple products) will feature a smaller dock connector. What hasn't been so consistent is how many pins will be in it, we've heard everything from 19 pins to 8 pins. However, this question may have just been answered..
Earlier we reported that iOS 6 hints at a taller iPhone screen and an extra row of icons, and now it looks to be hinting at a 9-pin dock connector; possibly the smaller one we've been hearing about. Although this may not be the case; all that's found is a reference to a new iOS hardware feature called “9Pin”, we're only assuming this is reference to the dock connector, obviously it's not a sure bet.
While a smaller dock connector has it's upsides like Apple being able to add new and more technologies into devices, there are also some downsides. All current accessories and cases you have for your current devices will be obsolete, so you'll not only have to buy new ones but wait for the companies to come out with updated accessories and cases.
Of course the upsides outweigh the downsides. Apple will probably come out with an adapter for older accessories to work with the smaller dock port, and if not Apple a 3rd party will be happy to provide one. As far as the cases go, new and better technologies outweigh having to buy another case, that's plain to see.