I must admit that I haven't really noticed any deficiences yet with my FZ6's stock suspension. The stock Dunlop tires have a funny "squirrely" feel on uneven pavement or when encountering "road snakes" (longitudenal tar repairs), but I'm fairly certain that's not the suspension's fault. I know that I don't push myself or my bike anywhere close to our collective limits, but I don't ride it like it's a Lambretta either.
I am inclined to invest in a "better" set of tyres first before performing suspension mods. But that's just me. Oh, and more bling.