firstly, this program rocks! i'm surprised by how easy nitrotracker is to use, and i'm so pleased that people went through the trouble to create it!
the most significant feature that would help me is the ability to write notes at the top of any pattern. in order to compose, i need to have a physical notebook beside me to keep track of what pattern is for what part of the song, which channels represent which instrumental lines [ie i use four channels sometimes to play chords for one instrumental line], etc. being able to write this information within nitrotracker itself would be awesome.
other features that would be nice (but aren't what i care about as much) :
1. ability to change BPM anywhere (this was already suggested
http://modarchive.org/forums/index.php?topic=1565.0here)
2. ability to change how many cells are in a "bar" [ie currently it is 8 cells]. this would make composing in 3/4 time easier. actually, even better would be to have not only horizontal lines indicating a "barline", but also (less emphatically-coloured) horizontal lines to separate beats. that is, in 3/4 time i might have two cells for every beat, for a total of six cells per bar; and of the six cells that make up a bar, two horizontal lines would separate the three beats (of two cells each) in that bar.
3. ability to switch between having pitches notated with sharps or flats.
anyhow, keep up the good work!