This might kill 20 birds with one stone. A turtle-logo-ish plugin would allow non programming oriented(and kids) to make great use of Paint.net, as well as allow advanced people easy control. It would also allow use of many simple text type examples on the net as well as allow for an easy scripting type language use inside Paint.net. Why not use a Logo program and import it, you ask? Because within Paint.net, it would allow flexibility, and give you features that already exist on the net(why reinvent the wheel)without needing to add them to Paint.net. As a plugin you could develope it independently or Paint.net, and it would require no learning curve.
I've seen requests for being able to locate points in a layer, Logo already can do this easily. It would also add degree ability(etc 360 degrees). And you could easily create perfect circles, squares, and complex shapes that might not easily be drawn(I was gonna suggest the circle tool change colors or change shapes on perfect symmetry before I thought of this). It might also reduce the need for "brushes", a feature I saw a request for that I thought was a good idea. It adds recursion(granted, you might need to add an emergency stop button in the plugin window for infinite loops) to make trees and stuff. Users can also build one tool upon another easily, and share their tools with one another.
You can add access to internal effects, adjustments, tools, making it a scripting language of sorts; if paint.net updates something, simply create a new plugin to address the issues, and not the scripting of the language.
Consider this:
Microsoft Windows Logo32.exe takes up about 860K and includes multiple turtles, and sounds and features that could be written out of the plugin, so it would take less space. Logo/Turtle is a language of math and graphics, perfect for programs like Paint.net, and this plugin would set Paint.net above all other programs of it's class allowing people of all experience groups powerfull and easy abilities.(I could go on with more, but I'll try to limit this in case you people think this is really stupid).
I would try to write this plugin myself, but I'm having trouble making a plugin that makes a simple point on the screen in C#, 8P.
You can even make a free plugin of this type to entice, and a more powerfull one that costs(a reasonable price) for more professional usage. If ya want me to go into more detail about how I think something like this should be implemented in the effects in Paint.net, inquire(before this gets locked). I also have another great plugin idea(even better) but won't post it until I see how this thread does. I wanted to post a picture I made with Microsoft logo http://www.softronix.com/logo.html but don't know how to upload it, so I can't(it's a .png).