Vietnamese: To group or not to group

Victor Mair at Language Log has an interesting post on a proposal to group written syllables into words. One correspondent informs him:

If Vietnamese were written as words, and not as syllables, there would be less need for diacritics (tones and "special"–in the sense that they lack Western alphabet equivalents–letters) because an equivalent amount of information (cues) is provided by the word division.

By adding information up front of one sort [word division], you get by with less information of another sort [diacritics]. Word division in orthography means that society and its individuals have invested resources in an upgraded system that rewards users with greater clarity for less effort. You put the effort in at the beginning–deciding the rules and learning them.

As a concluding remark, Mair observes:

It is remarkable that, although Chinese, Japanese, Korean, and Vietnamese have four different writing systems, they all are vexed with the problem of whether or not to join syllables into words. That, I believe, is the result of the latter three still retaining vestigial traces or influences of the Chinese characters. But even character writing could adopt word spacing if enough of its users would agree to follow such a norm.