In the case of Athens it is not very fair to judge the Games under the circumstances in view of the very difficult financial condition that Greece is.
But lets put some things straight
1. Organisation wise the games were successful much more than some of the preceding games wanting it or not.
2. The opening ceremony was an artistic event and as such, not everyone will like it or has to like it for that matter. It may have appealed more to people that have a specific background and specific educational background (and you can see than sometimes in the nationality of the commentators) while others failed to connect with it because they could not, or the creators failed to make them, understand the message. It was not some much what was shown it was more a message that the artist tried to present. It was not the technology or tricks shown it were the message. And believe it or not the whole Opening ceremony had a single story to tell which was unique in that respect compared to any other before or since.
3. The problems of the post-game use of the venues started long before Greece was in any financial constraint and just mirrored a certain disrespect to public property and funds that the Greek politicians and society has developed in the last decades and still, unfortunately has.