I know, a lot of people made suggestions how to improve music notation. Often they come with some pros but also with a lot of cons. I came up with a system, that hasn't cons. And if you find cons, they are very little or even arbitrary. But the pros are huge!
Instead of 5 lines, this staff has 6 lines, grouped in two 3-liners (call the 3-liner a "triple" for now).
I was always worried, 6 lines could be too much and look too crowded. But if there is a gap between two triplets, it doesn't look crowded anymore and the eye can very quickly determine the position of a note.

The key of the concept is the triple. One triple ranges the from lowest note hanging note to the highest sitting note 7 notes in total. This are all notes of an octave. For instance, the D is always on the center line of a triple, no matter where the triple is placed. Up and down from the D, the staff is symetric (same as the keys are on a piano keyboard). That the triple ranges from A to G in alphabetic order is a neat coincidence. (Or maybe not?)
Ledger lines are as well very easy to read, as they are made of the same triples. Each note has always it's relative position within the triple. Furthermore the triples make ledger line counting extremely fast and intuitive; even for bigger ranges.
A greater stave for the piano would look like this:

Of course the bass staff can have ledger lines on the top notes, as well as the treble staff can contain ledger lines to the bottom. Same concept as is is today.
The rest of the music notation is as it is (♯, ♭, ♮, key-signatures, and so on)
An open topic is to invent more symbols besides the treble and bass clef symbol to indicate octave shifts. This would make 15/8va¯¯¯¯¯¯¯ and 15/8ba________ notations obsolete. For shorter ranges the va/ba notation makes sense, but somtimes it spans over a page and just crowds the sheet music.
I think in total 7 octave indicators should be enough. Something like this:
TTT (Treble clef 15va)
TT (Treble clef 8va)
T (Treble clef)
C (Treble clef 8ba == bass clef 8va)
B (Bass clef)
BB (Bass clef 8ba)
BBB (Bass clef 15ba - in case you play organ or own a Bösendorfer Imperial)