1. I don't believe for a second that there are even as many as half a dozen 4.0 ready apps in the app store. I guarantee you that won't even change, today.
2. All Apps Re supposed to run without the need for modification, but this is an outright lie from Apple, as many apps do not. iTeleport, Air Video, StreamtoMe, Call of Duty, to name a few. There are many more, just from my collection. Probably thousands total.
3. Apps should be ready first. The damn app store should be 4.0 ready before they even flip the switch today, as its completely false advertising. Nothing will work as advertised today, and ill be uselessly complaining to Apple about how they have no concept or concern for what's best. They did this with the iPad when developers had a lukewarm reaction to the SDK, and now it seems 4.0 has failed to garner much attention either. The majority of devs of the 225,000 apps are content to sit tight and count de moné with their 2.2.1 compatible apps.
How about just being happy to receive a world class upgrade from a world class company FOR FREE! I swear, some people can find pimples on Cupid's butt...