Of all big companies, Apple should be amenable to a straightforward explanation that sometimes simplicity is the right design, and that "adding features for the sake of adding features" is wrong.
We've had an application rejected for this reason as well. In our case, they didn't even describe what they didn't like besides "not enough functionality". Our application was quite a bit more complex, and we could prove there was demand for such an application. I get the feeling they guessed at the application's functionality based on the name and didn't really check it out (it wasn't a particularly great name).
We went through the appeals process. It was very unhelpful. I got the impression that until we responded "we have updated the application", any objections were routed to the same unreasonable person that rejected us originally who didn't care to look at the same application twice.
We ended up adding a "feature" in a completely superficial way. We took an existing feature of the application and we exposed it as a top-level menu item instead of making it appear in the context where it makes sense.
As soon as we told Apple that we'd added a feature and they could verify that there was a new top-level menu item on the first screen of the application, they approved it. It was essentially the same application that they thought didn't have enough functionality, except rearranged slightly to make the functionality obvious to a reviewer that doesn't look past the first screen.
As far as I can tell, there's a lot of pressure inside Apple to churn through reviews as quickly as possible, and the review process is getting sloppier. Things get approved when they have glaring faults, and things get rejected because they didn't make a good impression in the first few seconds a reviewer looked at it.
The first time South Park was submitted to the ratings board 5 times, it got an NC-17 (to wit: patently adult material, a rating assured to destroy revenue). Then, with nothing more than a name change (the arguably far more vulgar South Park: Bigger, Longer and Uncut) the rating was changed to a much more market-pleasing R. Sometimes getting approval just takes a well-placed phone call amounting to "c'mon, people, don't be stupid about this."
There is a rejection appeal process. Use it.
Of all big companies, Apple should be amenable to a straightforward explanation that sometimes simplicity is the right design, and that "adding features for the sake of adding features" is wrong.