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It had never crossed my mind, but of course piano keyboard layouts are arbitrary and -- like mousetraps -- innovators are bound to try to improve upon them. in 1882 Paul von Jankó devised a keyboard with a 6-6 layout. As described at the Music Notation Wiki:
Because it has an isomorphic layout, each chord, scale, and interval has a consistent shape and can be played with the same fingering, regardless of its pitch or what the current key is. If you know a piece of music in one key you can transpose it simply by starting at a different pitch because the fingering is the same in every key.
This provides much more consistency than the traditional keyboard layout where each chord, scale, and interval has multiple shapes and requires learning multiple fingering patterns. On the Jankó layout there are twelve times fewer chord shapes and scale patterns to learn. This greater consistency also improves awareness of interval patterns and harmony, and makes it easier to improvise and play by ear.
You can go to the following link to fiddle around with Jankó style isomorphic keyboard.
Because few pianists were willing to relearn their repertoires for the new keyboard few Jankó style pianos were ever built. Lack of demand eventually led to their demise.