iPhone only multitasks system apps but it does not multitask third party apps. It doesn't do very well when lets say, you got a notification. For example, if you're doing one thing, the notification comes with a pop up transparent window right in the center of the screen, and that's for one notification only. Android, RIM and WebOS has far better notification systems that are far less obstruve, yes far more informative, while being able to handle multiple event streams. In terms of notification system design, WebOS tops the cake, followed by Android, then RIM.
Multitasking is one thing. But multitasking is not that useful if the system cannot notify you of event changes in the background related to those tasks in question, allowing you to respond to state changes in that process. In other words, multitasking + event notification is the only form of true, productive multitasking. Example. Android lets you know when a download and an application has finished installing, while you're doing doing another application. iPhone does multitask in the sense, yes, you can download and update apps on the background while you do something else, but it does not tell you when the installation is finished.
Widget? Not needed? Actually once you use them I find them incredible handy. A phone is about providing real time information and messages to you. Widgets do that. They are updated constantly in real time without you having the need for an app to open it.
iPhone does not nail email and messaging perfectly not by a long shot. Blackberry does it better, especially when it comes to the constancy of push messaging. iPhone 3.0 added push notifications but its not as good. If you got multiple notifications, the last one is the only one that will be displayed on the screen. You don't get a unified message and event timeline that explicitly describes who the sender, what sort of app or protocol (Facebook, Twitter, Gmail, Yahoo Messenger, Yahoo Mail, AIM, Windows Live,...) right in one single view.