Following on the heels of PodcasterGate, another App has been denied entry into Apple’s iTunes App Store: Mailwrangler. The reason, according to Apple (as cited by developer Angelo DiNardi, via Daring Fireball):

… Your application duplicates the functionality of the built-in iPhone application Mail without providing sufficient differentiation or added functionality, which will lead to user confusion. …

And:

… There is also no way to edit an account once it has been added. …

The latter is a gimme, and the developer acknowledges it, though feels is a capricious enforcement. The former?

Many developers are still in an uproar over Apple’s tight-fisted control of the App Store, and others are distracted by counting the huge heaps of money they’re making, and Google’s “open” Android Market looms on the horizon, we’re left to wonder how this will shake out in the ecosystem.

Some have theorized that Apple rejected Podcaster because iTunes is a revenue stream for Apple, and they don’t want any precedence set for bypassing iTunes, even for “free” podcasts. But MobileMail’s Gmail functionality doesn’t generate any revenue, does it? And all the calculator, weather, etc. App’s already duplicate functionality, so what’s going on here?

We’ll take a look, after the jump…

Since Apple doesn’t seem interested in pre-screening Apps before developers invest time and resources in them, these last minute rejections will continue to throw cold water on the iPhone App Store ecosystem. The results?

Some developers will learn to stay as far away from the 1 ton Apple elephant, their money and premiere Apps, as possible, and content themselves with other areas. Others will simply go elsewhere and develop the next generation of miracle apps on Google’s platform instead. While a few may keep throwing Apps willy-nilly against Apple’s fence, hoping something will stick.

This isn’t a computer. We get that. There will never be unfettered access. It’s not a lock-box either, however, and by remaining unclear, and worse — seemingly uncommunicative and uncaring — Apple will kill the developer community the iPhone Mobile WiFi Platform will need to truly become the Next Great Thing.

In that regard, Apple also needs to trample with extreme care.