"one would be able to see the words and be inspired."
Is by tzitis, but there is not command (from the holy one blessed be he) to see the mezuza the command is to write it and set it on your door/gate post
It might be because is needs to be a scroll
Rab Judah said in the name of Samuel, If one wrote it like a letter, it is invalid. Why? — Because of the inference that is made by the expression ‘writing’, which is used here [in connection with the mezuzah] and also there in connection with the scroll. °10
(°10) In connection with the mezuzah it is written (Deut. VI,9 ): And thou shalt write them, and in connection with the Book of the Law it is written (Ex. XVII, 14): Write this for a memorial in the book; as the latter must be written with accuracy as to spelling and upon ruled lines, so the mezuzah too must be written with accuracy and upon ruled lines. Rashi also suggests the inference from the writing of’ a divorce (lit., ‘a book of divorcement, v. Deut. XXIV, 1), which must also be written with accuracy; but see Tosaf. s.v. vc,f
R. Helbo said, I have seen R. Huna rolling up the mezuzah beginning at ‘one’ and finishing at ‘hear’;