German still has a ways to go with some of the vowel digraphs (ei and eu could perhaps be replaced with ï and ë respectively?) as well as find new uses for redundant c and v, not to mention trigraphs (sch) and tetragraphs (tsch). There’s also the “Sie” conundrum.
Well, "ä," "ö," and "ü" were originally digraphs ("ae," "oe," and "ue"), until the trailing "e" was reduced in size and move atop the leading vowel, where it eventually degenerated into the "Umlaut." In the font "Fraktur," the "s" was written differently, depending upon whether it was medial or final. I believe that the lovely "ß" had an equally interesting story behind it - sadly, what with the Orthographical Reform of the 1990s, its use is in decline.
I see no problem with tri- and tetragraphs; the corresponding sounds are consistently spelled that way, and - conversely - the letters, when arranged that way, always represent the given sound (except when in juxtaposition in certain rare compound words). The point is, after all, consistency - not brevity.
Sadly, too, many beloved words are falling into disusage or are actually being actively proscribed, especially forms of address: "Fräulein," "Herr Ober," "mein Herr," "Herr Student."
And that the Genitive Case is quietly expiring is a well-known phenomenon.
Ihr ergebendster Diener