Would it be advantageous for Japan in the global business market to shift from using characters as its primary written language form to a primarily Romanized written language form instead?

In the Meiji era, there was some academic discussion about Japan converting entirely to romaji (or even to take French, German or English as their language!). The biggest of many problems with such ideas is that they would lose their ability to read their own history and literature, and not be able to connect with their past. As for using romaji only for business, almost all Japanese (at least any who use a computer) can work well with romaji.

Hasn't Japan done rather well in the global business market? These days with pocket computer dictionaries with handwriting recognition available on a smartphone it's possible to look up any Kanji in seconds. So there is even less of an excuse now to use romaji as a crutch to starting to learn to read Japanese. Romaji is a dead end. When I look at piece of Japanese text on my Mac with no additional software I can press control-command-d and get the reading an meaning of the Kanji (or word) that I'm looking at. It look about a second to look up the two words in the Tamura-san's example to determine the meaning. It's even possible to OCR text with a small scanner, though your results may vary. Almost everyone in Japan is literate so it is not beyond the capabilities of the averagely intelligent person to learn Kanji. With the tools available now, it has never been easier to learn Japanese, but that also goes for music. It's easily possible to have better studio equipment on your phone than the Beatles had. In the end it's not the equipment, it's practice, motivation and choice of spending the time to do so which puts people off. If your question had been "Wouldn't it be great if there were more texts with furigana to entice an adult learning Japanese?" then I would have supported you wholeheartedly.

Korean did that with their inventing letters, Vietnamese dumped off Chinese characters and romanized. I agree that using smaller letter set gave some advantages, common letter set with dominating language also did some. However, they also lost something else by doing that. Even Japanese do not remember how to write Kanjis recently, because of PC. Reading skill is still necessary though. If computer usage and communications will move more to audio-based, importance of written text will decrease in near future. So I do not support that idea to take such a risk at this point.

As others have pointed out, Japanese has a truly exceptional number of homonyms, due to borrowed Chinese words.  The only way to disambiguate these, aside from context, is through the kanji.  These words are rarely used in spoken contexts because they are so easily confused. There's an argument to be made that they don't need so many kanji.  They could probably get by pretty easily with 500 or so, just to disambiguate between words.  But this would require a complete overhaul of the written language, and there seems to be no particular appetite for such a revision, aside from the complaints of people learning Japanese as a second language. Korean has many more sounds than Japanese; so, they were able to rid themselves of kanji without having this problem. Rather than change their language, it's probably more productive for them to just learn English.

Have to agree with Tamura. There's soooo much in those characters than just an "alphabet." You can "read" them without even being able to pronounce them and when they break down to the simple alphabets (hiragana, katakana, romaji) it's really hard to read. There's even a phrase for the strength of kanji: "kanji power." If you know them you get far, far more return for your effort to read things than hiragana, katakana, and romaji combined. This is from the perspective of a JSL speaker. If you ever really get to know Japanese and its written form you'll never, ever ask that question.

Where is the constituency that would make this happen? It is not going to happen. Also, Japanese has such few sounds that Kanji is really useful to disambiguate meaning.

Everything said here about technology making Japanese easier to use is correct. However, it's still the case that kids don't know enough kanji to read the newspaper until late in high school, let alone more complex books. Moreover, it is a huge barrier to communication with the West. Japanese people are generally horrible with English, and this does have at least something to do with the fact that so much time must be spent learning kanji. I love the Japanese writing system because it's interesting and rich, but it certainly is not as practical as a simple alphabet. All that said, it's not practical to switch systems and it would cut them off from their history, as Koreans are finding now that their knowledge of Chinese characters has become extremely minimal.

Japanese is a beautiful language because of lots of characters because each character evokes sentiment, impression or emotion. When you see/pronounce the character for rain, 雨、it brings you the image of rain, the smell of wet trees, the sound of rain...it is not just a combination of letters like English, r,a,i,n., so when you spell it in romaji, AME, it doesn"t call anything in your brain.

It is less relevant than ever now that there is already full information processing infrastructure to handle Japanese script. Embarrassingly, as late as 1987 J. Marshall Unger's book "The Fifth Generation Fallacy" claimed Japanese script was completely incompatible with computers.