There comes Chinese characters, which are exactly the opposite of your definition of "optimal": Chinese characters are not an alphabet, they do not carry phonetics, they carry meaning. And, guess what, this is arguably better.
Why? Because phonetics tend to shift quickly. In a few decennies any spoken language has shifted, vocalisation is different, especially when the language is used by loosely coulped communities. And then you have to adapt spelling to new pronunciations. But what do you do with old books? And how do you keep the language united? Chinese characters, by allowing different pronunciations without changing their written form, do fix this issue. This has helped China to stay centralized for a long time, and share one common continuous cultural ground.
So, if optimal means "can be shared by more people for a longer period of time" maybe the optimal language would need to add an articulation, and represent meanings instead of sounds.