While we know quite a lot about what Windows Phone 7 will and will not include at launch, presumably due to being rushed to market, there are always a negative things that pop up that catch out attention.
Over at .NET Reference blog, the author has posted a laundry list of 'haves' and 'have-nots'--most we're aware of, but here are a few that we weren't:
- No RAPI support. There will no interacting with a WP7 device via the desktop. Obviously there will be some synchronization with Outlook, but nothing the developer will have control of.
- Applications must be Silverlight 3. Silverlight 4 will not be available for WP7. (Edit: It's actually Silverlight 3+)
- No Bluetooth API. While there is going to be Bluetooth support on the phone, there is no Bluetooth API.
- No Video Capture Support. Phones will have a camera but not video capture support, and also no video brush. (Edit: for 3rd parties, not OEM)
- No Outside TrueType Fonts - Microsoft experts claimed that you will not be able to use TrueType fonts other than the ones delivered with the device. This limitation makes since, how would you get them on the device. While there is supposed to be support for embedding TrueType fonts in your xap file in Silverlight 4, this will not be the version used on the device.
No Remote API (RAPI) support refers to the ability to use the desktop to manipulate the file system--since users won't have access to that anyways, it's no surprise that it's not there. In addition, RAPI is also used to remote-control the phone or treat it as an extension of the desktop--so at least initially that trick is a no-go, however apps like 'My MediaRemote' get around this limitation.
Devices like the iPhone and Palm Pre both launched without video support initially, so the fact that WP7 lacks it too at least share precedent. We expect that function though to be forthcoming in maintenance releases. Still a bit odd though as we've seen the LG Panther list 'HD 720P' video recording on the box.
The lack of Bluetooth API means not much support outside of basic headset support. Come to think of it, what's the status on A2DP on launch? We'd hope for a music device it would be there...
Finally, the author of the blog notes this complaint:
The TechEd demos of WP7 applications had a common theme; they crashed, hung up, or gave peculiar error messages. For a platform that is going to be delivered in the October timeframe (3 months away), it is hard to have much short-term faith in the new platform.
That's something we have not heard much of from anyone, so whether or not these were flukes or not, the sentiment seems to be the opposite. Take it with a grain of salt but also consider it a possibility.
Update: Some of our more knowledgeable visitors have clarified some of the above; read below.

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