Wait until you hear this! I paid for Adobe CS2, but when CS3 came out, those cheap bastards made me pay them for an UPGRADE just to get some more features that I think should have been in CS2 to begin with! They did it again with CS4 and CS5! Unbelievable! Somebody must stop them!
The way I see it is like this. You bought an app a year ago when iOS 3 was out. You decided that you liked the app and you paid what features it has. If the developer adds new features then that is up to them. I am in the process of updating all of my apps to be iOS4 compatible now because I want to make sure my users have a good experience with my apps. I also didn't realize that all 99 cent apps were making millions of dollars! I must have missed that boat.
I don't think that multitasking support should be required, but it's a bonus that most users appreciate a lot. I'm not going to hold off on buying a game because it doesn't have multitasking, but it'll bug me. However, the screen orientation support thing I do find necessary, and I'm really happy that Apple is forcing developers to add it in iPad games, activated by simply tilting the device like in default apps. This is probably in part due to the screen orientation lock, so if you're playing tilt based games, you don't have moving UI's. Even so, there's a virtual orientation lock on the multitasking bar for newer iDevices. I hope Apple starts cracking down on iPhone games for that too.
The app store is a very competitive environment, already made difficult enough by an ever-changing set of rules. The developers who make great iPhone games think that these difficulties are sometimes worth the potential exposure that the App store brings them. The more restrictive developing for iDevices becomes, the better odds that some of those great developers are going to take their business elsewhere.
