I like my Nike Plus system. It makes it easy to track runs, I don't have to write down or remember numbers, and I can see some history of my runs easier than I could any other way.
However, there are definitely things that I would like to see changed.
First, the module that attaches to the iPod is a little small, and it's hard to keep track of it. I'd rather it be a little wider, and match the size of the Nano better (or the iTouch). It would be nice if it were a pass-through of some sort as well so that I didn't have to take it off to sync up the iPod. I always worry I'll lose it. You can see it on a Nano to the right.
On the web site, they need to allow a few things.
1. Edits: I've accidentally stopped the device, or started it late sometimes and I have a treadmill, a watch, and known courses. So I should be able to mark a distance. I've also had the iPod die (lack of battery) and I would like to be able to use MapMyRun.com, my watch, etc. to edit the run.
2. Manual Entry - A few times I haven't had the NikePlus, but I'd like to track that run in one place. The lack of capability to enter those runs makes me want to use some other system to track my running.
They also should smooth the interface. I realize that the Flash stuff seems cool, but I can't easily link people to something and I can't quickly get the code for my runs. It's a pain, 4 or 5 clicks, to get the code for a run.
Overall, however, I think it's the beginning of a great system, and apart from the iPod, a cheap way to automatically track your runs.