Compared to modern films that have followed it, no it's no longer shocking or as thought provoking as perhaps it was when it was new. But this can be said of most masterpieces, time, analysis and other works copying it always waters down the impact any form of art has.
However, when considered for what it is, a film shot well before its time, it is rough masterpiece imo. I say rough as I think the story and its presentation are too cynical, it's thoroughly bleak. I know this was his intention, but i'm not totally convinced a more balanced version wouldn't have worked just as well and would have been less sympathetic towards anarchy, which no matter what anyone says, is a good thing imo.
It's an excellent film though, based on an excellent story, it's just not standard viewing, there's little obvious reflection with the real world, only veiled hints as to how its a reflection on parts of society. This means you have too think about it all from start to finish, that's not always something people want when watching a film or reading a story, which is fair enough!
)