do you play first position? third? a G would give you a lot of room in key of G. for third you'd want an F, or if you know a lot more than me, you could use a C and find your way.

a chromatic has all the notes in an octave, and several octaves depending on which one you get. it would definitely give you room to do more. i use hering 48's, and i use them in first and third positions. this has expanded the variety of my sound a lot. and it IS possible to play second position on a chromatic, but some of the notes are laid out opposite of a diatonic, so it can be a challenge to get things flowing well.