A marquee select, copy/paste, and guides are borderline required features. With those, this would be a killer app, no question. As is, it’s still really, really good.
Since there are no keyboard shortcuts for tools, it would be extremely convenient to use the keyboard to switch to a glyph. That way, you could toggle between the glyph you are currently working on and others with similar elements without moving the mouse off the canvas. I know left/right moves through the glyphs, but I mean flipping between “w” and “m,” for example.