I'm not sure about the alerts. But the mutlitasking isn't true multitasking since the apps themselves aren't still running, just services they use. I can see this being good for performance and battery but wonder if it will limit some functions?
Just wondering what multitasking feature you feel they are missing? I was actually pretty impressed with what they came up with. It seems like they hit all of the main multitasking issues people wanted - streaming Pandora and other radio apps, GPS being able to keep track of you/give directions without the app in the foreground (they showed TomTom and Pandora running at the same time - pretty cool), letting downloads/uploads continue with apps that aren't the foreground app, and so on.
The fast app switching, where basically an app keeps its saved state and lets you easily go back and forth between apps, may not have the secondary apps actually "running," but isn't that what we mean by multitasking most of the time anyway? If you have multiple programs open on your computer at once, for most types of things you can't really actively do things in more than one window at once. You "fast app switch" your attention back and forth. I may think of myself as "multitasking" when I have several things going on at once on my desktop - following Twitter, playing an online game, checking my email, reading an online forum - but the truth is I'm not _really_ doing all those things at once. I'm just going back and forth between them quickly. iPhone 4.0 offers a very elegant way of doing that, especially given the small screen real estate, with a lot less clicking in and out of apps. Hopefully this will preserve processor/battery. In the presentation, they said the background apps are consuming no CPU power. On your desktop, that may not matter, but on a phone, it's crucial.
I also liked how they said in the Q&A that you won't have to _close_ apps. They said if you have to use a task manager to close apps, you have failed with multitasking. I agree with that 100%. Before my iPhone I had a Windows Mobile phone and a Pocket PC before that. Sure, they multitasked and kept a bunch of apps open at once, but more often than not it slowed the whole thing down to a painful crawl. I spent more time closing apps to free up the CPU than I ever spend opening iPhone apps now. It's also one of the criticisms of the Palm Pre and some Android devices that can get hung up when there's too much going on, requiring the user to shut things down. It remains to be seen how smoothly multitasking will actually work on the iPhone, but I think they've got the right idea.
I'll be really curious to see how the ads work out. They're bad enough on free apps now. Can only imagine how bad things can get, especially if they start putting them in paid apps.
There have actually been ads in some paid apps already. I think it was the CNN app that caused a big outcry when it first came out with ads before the videos. My feeling is that if something is an ad-supported free app, the new iAd thing is no worse than what we have now (the banner takes up the same amount of space as most banner ads until you click it). It may even be better, since the potential is there for the ads to be of much better quality. The Toy Story one they demoed was nice - I know my daughter would actually like playing with that ad, which included pictures and games. Honestly, the Disney iPhone app is really mostly an ad anyway.
I will be aggravated to have paid apps start including a bunch of ads, but I think that's up to users to protest if it happens. If someone releases a $10 app full of ads, people shouldn't buy it or they should leave reviews with how they feel about it. There may be some middle ground, too - personally, if there is an app that would normally be a $10 app that is sold for, say, $2 with ads, I'd be open to that. Developers are going to respond to what sells.