It's really not a mess. It's a solution to a problem, and it works well.
To give you an idea of how not-a-problem it is, many composers (myself included) prefer to read orchestral scores (so, a page will have roughly 15-20 staves) that are transposed. So, instead of reading each instrument in the same key, we see what each player is reading. If the concert key is C, I'll see the clarinets and trumpets reading in D, etc. I prefer it because you get a better sense of how the music feels to each individual player, and can better respond to any issues they're having.
It's a mess to look at, I guess, but to any reasonably well trained musician, it's clear as day and conveys far more useful information than the "cleaner" way of seeing everyone in the same key, which really just obfuscates what's really going on.
To give you an idea of how not-a-problem it is, many composers (myself included) prefer to read orchestral scores (so, a page will have roughly 15-20 staves) that are transposed. So, instead of reading each instrument in the same key, we see what each player is reading. If the concert key is C, I'll see the clarinets and trumpets reading in D, etc. I prefer it because you get a better sense of how the music feels to each individual player, and can better respond to any issues they're having.
It's a mess to look at, I guess, but to any reasonably well trained musician, it's clear as day and conveys far more useful information than the "cleaner" way of seeing everyone in the same key, which really just obfuscates what's really going on.