On plain texts and ciphers (a thought experiment)

[-JKP-]

I understand your point JKP, and you're certainly right. Still, it's a select club of Latin glyphs, a peculiar collection. Off the top of my head, Latin glyphs which are certainly missing are b d e f g h j k l p q t v w x y z.
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The "scribal" glyphs are certainly not peculiar. Whoever designed the VMS chose the most common Latin scribal conventions (with the exception of the reverse-c shape, which is less common than y in both Latin and the VMS), but if you put scribal glyphs aside for a moment, I completely agree that the remaining alphabetic glyphs, when evaluated individually, do not comprise a full set (or anything close to it), ASSUMING this is natural language.

Some people try to decipher the VMS by treating the scribal glyphs as substitutes for the missing alphabetic glyphs (and some simply don't know the difference), but this line of decipherment doesn't work because the VMS glyphs that look like Latin scribal glyphs are positioned exactly as they would be in Latin—this particular set of scribal glyphs does not have the flexibility of natural-language alphabetical glyphs. That's one of the reasons simple substitution "decipherments" do not work.

If Voynichese is heavily abbreviation info or coded info rather than narrative text, the designer might not have needed all the letters or might have indicated them in a different way (e.g., variations in shape, variations in position, markers, modifiers, etc.).

But let's assume the VM mirrors Latin script looks by intentional design. What could be the point of that? Anyone who can read will see that it's in fact not normal Latin script. And those who can't read won't be able to read it either way. 

Let's say you were a spy dispatched to Constantinople or somewhere where the Latin alphabet might be vaguely known but not used (e.g., a region that uses Cyrillic or Arabic, for example). If you wrote the information so it vaguely resembled Latin, it would probably not draw too much attention from the local populace. It would superficially look like Latin but might contain confidential information. I'm not offering this as the best explanation or even as a good explanation, but there may well be reasons one might want it to look like Latin.

The other possibility is that the designer used Latin shapes and conventions (for their own purposes) simply because they were familiar and thus it would be easier to write a whole book in Latinesque glyphs rather than in something completely invented.

I would even go as far as saying that your observations are an argument against people who propose the VM was made to deceive. Who exactly do you want to fool, if you go through much effort to make it look and feel like Latin script?

I don't know why a whole book would be written in an inscrutable script that was something other than a simple substitution code. I only know that a medieval physician's daughter asked her father, "Why write in code?" and he responded that it gave the information more value, made it seem more important, and that one was giving away less (in the sense of trade secrets) by writing it this way.