Of course it is. It ain't a "smartphone". No proper smartphone would have that kind of crappy calendar.
I think we beat up on WinMo and HTC a lot for not giving us everything(as well we should

) but at least we get the "important" stuff done right. Like Calendar and email. Sure blackberry does that well too but that's where it stops. At least WinMo does try to do everything. It may stumble, but at least it tries. The iPhone gives a great multimedia experience but it doesn't even try to give a good PIM experience...
Hence, "It ain't a smartphone". it's a pertyphone.
There are already TONS of third party apps available for the iPhone, some of them extend the functionality to a point almost unbelievable (Photo Browser and TuneWiki are only two ingenius examples).
People seem to forget that the iPhone is Apple phone No.1. Look back in time and remember the first HP Pocket PC Phone (this was MY first WM phone) and it is a difference like day and night.
I don't say Apple got it 100% right the first time but the GUI/OS/touch operation are already so good on the iPhone, the steps to improve applications and to introduce third party apps (with the new SDK soon to come!) isn't THAT big.
HTC has a great potential and so does WM, especially since WM5/6. Symbian concentrated too much on the multimedia functions and I don't like using it. I also own a Nokia E90 and a Nokia 95/95 8GB and whenever I'm powering up one of these babies again, it is like looking at some children playing software engineers. The icons are too kiddie-like, the whole Symbian S60 3rd software operation experience reminds me of kids playing with a colourful learning computer, it just doesn't have a professional touch.
Windows Mobile is much better in this domain but still, I get the feeling that Microsoft doesn't realize what Apple put on the market with the iPhone. It is not about the crappy GSM hardware without UMTS/HSDPA or the crappy camera without video function. The iPhone is the 21st (compared to the other phones on the market more likely 22st) century cell phone regarding the GUI/OS/touch operation and to add some hardware functions (3G, better camera, GPS) and software apps is almost a piece of cake now.
If Apple gets it right with the iPhone 2 (or more likely 3), manufacturers like HTC, Nokia but also Software companies like MS or Symbian will be in trouble. Whowever used the iPhone and didn't just play a couple of minutes with it knows what I'm talking about.
For Microsoft, there should be three priorities in WM development right now:
1. getting rid of the "sluggishness" of WM operation (which probably requires a completely new programming from scratch and I wouldn't mind if MS would use Unix/Linux based code to get it right)
2. forcing hardware manufacturers to make use of the VGA resolution capability because whenever I look at my TyTN II's display, I have the feeling of being thrown back in time a couple of years.
3. better support for exotic hardware and CPU/GPU combos
For HTC, there should be four priorities in hardware development:
1. better and larger displays with VGA resolution (at least)
2. better battery life and energy management
3. faster CPU/GPU combos with somehow lower power consumption
4. iPhone-like touch display operation
Yes, owning an iPhone and a HTC TyTN II may be the perfect combo (I still think that owning an iPhone, a HTC TyTN II and a Nokia N95 8GB is the perfect combo because the Nokia has a superb camera with superb photo/video capabilities) but the problem is that as soon as someone gets used to the iPhone, looking at the HTC/Nokia display and operation throws you back into the stoneage. This is actually my biggest problem and this is why I'm using the iPhone most of the time and other two ONLY if I really need some special functions (HTC for business and Nokia for family vacations).
Don't get me wrong: I'm a very open minded person regarding computers and gadgets, I still prefer Windows Vista on my laptops (mostly current hardware and 2GB RAM) and I had more problems with OSX Leopard in the past two weeks on my daugthers iMac than I EVER had with Windows over the past 10 years. However, if Apple puts an iPhone with UMTS/HSDPA, A2DP profile, a decent 5 MP camera and improved business usability on the market, it will be very difficult for me to go for another product in the future. HTC and Microsoft have a GREAT potential at their hands, I just get the feeling that they sometimes forget to look a little bit closer at the competition.
Which also reminds me of the crappy design of the current HTC devices, HTC clearly needs a better exterior shell designer because the HTC TyTN II for example looks like a WM device from 5 years ago.