I absolutely love this plugin, it's magic.
I have one suggestion: I'm currently running a bulk smush.it on approximately 3,000 images, and they progress stream is scrolling down the page... which I don't really care about. What I care about is - how long is this going to take? How far through am I? What would be really helpful would be a UI like Viper's "Regenerate Post Thumbnails" plugin. Just a progress bar at the top, and then everything else underneath.
Though to be honest, the only real data I need displayed is a progress bar, and any errors which the plugin runs into.