This question was made over 9 years ago. It made sense then, it doesn\'t make it now. Flash is hard on its way out; sup
My belief for pros:
My biggest con would be that Ogg is a bit behind in terms of compression and quality. But I would imagine it's being worked on. More importantly, if more people start adopting it, more people will likely join the the work on Ogg to make it better.
Competition is key as well, as there is no major player forcing Adobe to really do anything with Flash. So Adobe can control the market in terms of video content on the web.