What are the real obstacles of romanizing Chinese characters? Most people will say it is because there are too many homonyms in the Chinese language. But when I realize that homonyms do not bother people very much in oral communications, I begin to question this answer. As a matter of fact, Vietnamese writing system has been successfully romanized. They have a lot of homonyms too, but they are doing fine.   

Ever since Sejong the Great invented the Korean alphabet in 1446, Korean vocabulary has become a superset of the Chinese vocabulary. In other words,  hangul has no problem with Chinese homonyms.
Nong si gangdu va?

Romanizing Chinese would effectively sever the cultural and historical continuity, and it would also be detriment to the many minority topolects that share the same script.

You would need to romanize not only Mandarin, Wu, Cantonese, Min, Sichuanese and so on, but also the many dialects of these regional tongues.

Furthermore, you would completely lose the poetic charm that Chinese characters carry. Chinese culture and language would be much poorer without the characters, as they are a defining element of the culture.

There used to be a movement for abolishing the characters, since they were perceived as an obstacle to learning. This is no longer the case, and nobody would propose such a reform today.

Japan has long had not one but two alphabets, but still retains the characters, for the same reasons as stated above.