I started transcribing some songs for a friend of mine who is learning piano. I do simple songs for the most part, but sometimes also more complex pieces. I use Guitar Pro 5 and I find it impressive as it can easily deal with the complex contemporary music notation: the staff, clefs, key signatures, accidentals, note durations, articulations, codas, ties, tuplets, etc. Contemporary music notation is all one needs to transcribe songs. Most contemporary songs are simple anyway: they stick to a key signature and have repetitive note duration patterns. I just finished the main theme (one repetition of the progression only) of Grant Green’s "Joshua Fit the Battle of Jericho". It has four underlying chords and I am guessing that it uses the harmonic minor scale (I put it in D harmonic minor). Who cares really? It was pretty easy to transcribe.
Then I started on "Big Spender", which is another thing. I am still on the first page. The song mixes B and Bb, D and Db, G and G#, so on and so on. Almost every note on the 12 semitone scale is there. At this point I can’t actually keep track of the flats and sharps. I am not sure how a guy who is trying to learn the piano will figure it out (guitar is easy, as it has a tab). Hopefully that guy has good memory for music and will figure it out by listening.
The accidentals (flats and sharps) of "Big Spender" got me thinking of contemporary music notation. The problem with contemporary music notation and "Big Spender" is the staff. It comes with five lines only, which is sufficient for a standard and static heptatonic scale. A six line staff would have been better for "Big Spender" as it would have appropriately covered 12 semitones and we wouldn’t have had to deal with accidentals. Or perhaps just making the accidentals impermanent would have been sufficient (affecting the following note only rather than all same notes after that until the natural accidental).
I looked around for alternative music notations – mostly out of curiosity. I wouldn’t expect my friend to be learning another notation. Since tablatures pretty much cover guitars and basses, I looked specifically for piano, but found other stuff (I also found many "Dokument nicht gefunden!" pages; why is alternative music notation so popular in Vienna?). As it turns out there aren’t that many alternative music notations and none of those I found are that great.
The small letter notation was used some years back. As far as I am concerned, it has the same issues as contemporary notation (seven notes marked on a five line staff with accidentals). At least the notes are spelled out in letters, so we don’t have to remember them. Klavar was apparently developed specifically for piano. I think it makes a lot of sense, but it is specific to piano (you should check this forum out: http://www.abrsm.org/forum/lofiversion/index.php/t11765.html; some people actually get insulted when others talk about alternative notation, since traditional notation "has worked well". I guess traditional notation does its job, but why not make things easier if we can). Non-western music notation is more interesting. I would have thought Arabic was different with its quarter tones, but Arabic scales are mostly normal scales except for one or two notes flattened or sharpened by a quarter tone. Arabic music notation is basically the same as the traditional one, but with the occasional different accidental here and there. Carnatic music notation is interesting at first glance, but it also looks stuck around a heptatonic scale. Finally, I am still trying to understand the Byzantine music notation. It uses a starting note and then intervals describing how to get to the following notes (like for a shamisen). Once again though, it seems to have intervals corresponding to a heptatonic scale.
So I guess we are stuck on the seven note scale with five line staff since Byzantine times. I would have picked a six line staff with a small letter notation (12 letters) and accidentals for quarter notes only (as long as they are impermanent to avoid confusion).