For me it's not even about how the content is displayed (which is Adobe's concern), it's the user interface. HTML 5 could present everything in mostly the same

For me it's not even about how the content is displayed (which is Adobe's concern), it's the user interface. HTML 5 could present everything in mostly the same way, but still be an improvement because the browser would be aware of it all. Problems that I see only in Flash: - Fixed-size text in a fixed-size box in the browser. - Text that can't be selected/copied/pasted. - Unnecessary customizations to video player interfaces. - "Navigation" that is completely unable to interact with the rest of my browser, e.g. can't figure out what URLs things go to, or how to go back. - Needing to go to Adobe's own web site to bring up Flash configuration panels to edit further redundancies like Flash's own cookie storage, etc.