Hey, I've been visiting your website always once per week for some months for the NG to appear until I got to know it had been discontinued (yeah, too late).
StuffPlug is sill a very good plugin with many usefull things.
I can't think of only one think to implement, so my opinion: Go ahead and keep adding stuff to it...
You could do a kind of plugin extension. Releasing the essential things in the basic package, and making then other plugins extensible to download from somewhere. So anyone could build up an own StuffPlug with the favorite command bundles.
For example: A downloadable bundle with all kind of Google related (or anything posted above, goodideas, but too much if you're only using a couple of them at the end) commands ready to plug into the SP-NG and ready to run. Even with StuffPlug being able to catch new commands installed on the fly and add them to the current list.
Making StuffPlug customizable. Many commands are offered take the ones you are interested in.
Whenever you want to add new things you just have to release more packages and you're done.
I know, it some more work to make it possible, but it would be very nice and attracting IMPOV. After all, you are an allmighty plugindesigner, afaik. Everything is possible
Keep up the work