Not yet anyway, and does anyone have a copy of IE8 for Mac OS X laying around? Apple is slowing getting rid of all Flash on their products. They are not thinking about browsers at this moment.
That's not really true about Flash and browser. Apple are currently testing Safari 4.0.5 which includes a lot of work done to improve the way it handles flash (and to protect the rest of the browser against flash problems). This suggests that Apple are putting effort into flash compatibility, rather than just shutting the door on it.
As for unimplemented options, I would certainly have written code where there were unused pieces in for reasons of extendability or lack of time, or cut down features in some versions however I would never have any unusable options visible to a user, even for reasons of display layout.
I find the built in Symbian browser more than adequate, bearing in mind that I am using a portable device with a small screen i just want to do the minimum I need (I don't spend hours squinting at any phone). I've installed both Opera mobile and mini to try them, and uninstalled them both because they don't really offer me any benefit.
As of the N95 and N85, I would agree with you on the Symbian browser - its more than adequate. But as of S60v5, it needed more than the basic effort Nokia put into it.
I wouldn't even have unimplemented/incomplete options hidden - its a potential security risk. Until they're complete, they shouldn't be in the release version of the OS.