For better or worse, the only way to guess if this notation can be sight-read, is for someone to train themselves to do it. And to make matters worse, learning to sight-read for adults is so hard that it's virtually prohibitive. Every musician I know who can sight-read fluently, learned it as a kid.

So it's virtually impossible to try out a new notation system.

But my impression is that this would be phenomenally hard to read, especially in a live performance situation where your attention is divided between the sheet music and other stuff. If I were staring at a solid grid of text, and were to glance away for a split second, I'd be lost. Part of sight-reading for me is being able to read ahead by a few notes or even a few bars.

It may also be that conventional notation displays a lot more density on a single page, because a 16th note takes up no more space than a whole note.

The main problem I can see with that sort of system is that it probably would get quite unwieldy for decently complex chord patterns (try scoring a chord pattern up the keyboard, say, like what's at the beginning of Tchaikovsky's Piano Concerto 1 for a start -- http://imslp.org/wiki/File:PMLP02744-Tchaikovsky-Op23v1FSmuz...).

For other styles I think it would be pretty good; although the score won't be as compact, it might be easier to understand a "fake book" scored piece (ala what's used a lot in jazz) written this way, let alone pop (which often can be represented with a melody line and Roman numeral chords).