As a developer, I had pondered this very situation myself, but wasn’t sure if I was missing the point.  When developing applications or websites for a traditional PC/Mac scenario, with a mouse and a screen, you rely on the user moving a mouse around the screen and clicking on interface elements, or “hovering” over the element.  That’s the basic interaction paradigm.  However, with touch screen devices, you do not have a mouse pointer and you do not have the “hover” interaction element.

A prime example is Safari on iPhone.  A website that has dropdown menus for their navigation are a pain to use, because you cannot simply bring your mouse over the button and get the menu to show itself so you can continue.  Why? Because there is no mouse in the touch screen device situation for this to work.  So Safari on iPhone implemented a “long touch” that tries to help with this problem.  But it still doesn’t solve the problem.

Now imagine yourself as a game developer, or a user playing a game.  The games developed in Flash for traditional computers rely on the mouse, mouse movements, etc.  As a touch screen device developer, you are watching for gestures, such as taps, pinches, etc.  The simple fact being that games written in Flash currently on the web would barely work, if at all, if Apple allowed Flash on the iPad.  It would be very frustrating, even putting the performance and battery life issues aside.

Is there a possible solution? Of course. Adobe could work on providing Flash developers with API access to touch events instead of a mouse driven model.  But that still requires the software that has already been written and available to be rewritten.  Not a very good solution, but the only one I see.

Roughly Drafted Magazine has published an article with a few more technical details and insight into the problem and I encourage you to read it.  With all the buzz about Flash, HTML5 and Apple, the more educated you are on the matter, the better.