Flash is pain and should hopefully go the way of the dodo very soon, if html5 <video> with open formats takes off. BBC are being nudged to use <video> more (I think it's already available on iPlayer for Apple - and a BBC news site redesign is coming soon) and it can't happen soon enough.
By and large I'm of the standpoint that open software is preferable to proprietary software, except in circumstances where it might technically be a bad idea (I can only think of one). The appeal of Free and open software is strong, the benefits are clear and speaking as someone who works with it I do feel that the web should be a platform-neutral and standards-compliant medium.
There are a whole host, therefore, of problems that I might raise with use of Flash for things that have nothing to do with Flash because they could easily be done with web technologies that various platforms support (although I shan't start on JavaScript).
That said, for things which step outside that realm, Flash has been an understudy that is maybe even *closer* to platform-neutral than just providing a link to $randomproprietarymediaformat, as outrageous as that sounds.
Web functionality that otherwise would require some other client software than the browser - lots of video, access to webcams and stuff is only really available to users on GNU/Linux at this point because we have a Flash player that works, and the other platforms have Flash players that work, too. The alternatives would be windows and maybe mac desktop apps, or plugins, or just media in proprietary formats.
Whilst it might be nice to see a future where everyone's browser is playing them ogg audio/video, isn't the reality likely to be some thin wrappers for Apple or Microsoft's formats and DRM and so on?
It *is* nice to have something that doesn't require those things, and that end users can just sit and *use*. It's good to have functionality that people might want on the Linux Desktop.
In this sense Adobe (like nvidia, and id, and so on) has done something to support and foster Linux usage. It has taken them a little time and work and therefore cost them some money.
Yes, it's evil and proprietary and stuff, but it works for Linux users through conscious effort - and in the absence of a 1) viable and 2) widely adopted open source alternative. It is an option for people to live vicariously and use and develop Gnash, or in the case of video, simply grab it and decode it for themselves with, say, Xine - or even to cross their fingers and hope a morally proper alternative turns up at some point.