I think the "We'll give you the feature when it's seemingly ready" is a decent one - if you look at cut copy paste - you can see an inkling of it back in the 2007 WWDC when they're showing off Safari's Webclip (which is a point - the iPhone could do webclips in a card analogy similar to pre if it wanted...)
I think, like WWDC 2008, there might be some problems in double guessing Apple's long-term strategy. E.g. The opening up of the dock connector, and BlueTooth is HUGE. It really does bear shouting about - as it'll v. likely have a decent amount of time to the companies that were able to get something ready for a presentation in 2 months time.
I think it's worthwhile doing some castle in the sky thinking again -
Would you want a better camera. Or a digital camera that you can slave to your iPhone, to use as a remote previewer/options selector/remote photo taker? E.g. Think Eye-Fi that does Bonjour. You control your camera, take the picture, wifi it over to your phone, select what you want, an email a preview/lo-fi version off.
BT proximity sensing to activate things/ use to set devices in the home, security etc. If they nail the adding the BT /wireless to devices, and make it easy to do for new versions/retrofit, it could be a hack a day's paradise.
This isn't just "a phone, an iPod, and a breakthrough Internet device" anymore - this the digital conductor's wireless baton to control and view get data, send data...
To think that Apple can't do 2 things at once is ludicrous. Yes, it has a finite set of resources. v3 iPhone is a good indicator of Apple's momentum.
But as shown by there current update of Macs - Apple lays the ground for updates in products it's put out there prior to updating the software. They might not be totally in sync, but Apple can work around that. The BT has been dormant for pretty much a year, but now will have bigger potential functionality than many BT in other phones for example.
I haven't seen anyone here realistically say - no there won't be ANY changes to hardware, or say there won't be a new phone version by the end of summer. I might be wrong, but that's what i got last time i read this thread.
With the iPhone maturing, they have space in the Apple stable to add another line of iPhones, with different features if they want, rather than stop selling the iPhone 3G. They can then offer iPhone 3G at a competitive rate (and have decent margins) and also offer the new iPhone with some decent new features.
An iPhone can't converge everything, as there are physical limitations unless you want to change the shape and innards a lot - e.g. adding Flip like video capabilities at HD levels requires a shift in design. However, a lot of other devices have already been converged upon, with others known to definitively be being added -
e.g. WWDC 2009 will be v. likely be Ground Zero for SatNav phone convergence. Anyone still remember the Nuvifone?
We've already seen convergence with iPod at launch. The iPhone is the MID Intel pushed but hasn't made in quantity. It's the Tonchidot/Enkin device that could deliver in mere months (See Bill Gates' swan song keynote and how the iPhone could deliver that dream). Yes, there will not be everything in there. But it's an increase, over time.
I believe there will be a decent hardware upgrade. But even if not, in a way, other things already announced, and to be announced will be bigger in the long-run.