Note that no one's forking it to remove features. One Thing Well
There's an implicit argument I disagree with: Since we're dealing with apps which do One Thing Well here, the quotation may just as well state: "look! how they make the program less focused on a single task but make it more complex instead."
This, in my mind, basically means either (1) Notational Velocity in its original form was just perfect, hence the impossibility of removing stuff, or (2) Notational Velocity wasn't perfect but doing one thing well and we developers jumped in and broke the golden rule.
I disagree to that second possible conclusion, partly because I wholeheartedly agree to the first one.
All of us "forkers" try to make something entirely new out of NV. I want to transform it into a text editor for (Multi)Markdown files. Other want a full-screen writing environment. I don't want to add features to Notational Velocity. I want to change it; and I for my part am pretty certain that it will eventually evolve into something else, a consistent tool for the task of managing notes in my digital archive (Zettelkasten).
I use NV to navigate notes lightning fast, I do not compose them there. I rely on the aid of TextMate's powerful features there.
My personal aim will be a toolset which combines Notational Velocity browsing with TextMate editing and Markdown-powered preview. I could continue to work with Finder and TextMate alone. Only thing was, it's a pain in the butt, it was especially painful to search and browse notes. My system evolves around the possibility of changing its parts. Just give us hobby developers time to get our grips onto the code and getting up to speed with our ideas. Some may improve Notational Velocity for one purpose or another, some may break it entirely in the eyes of the userbase. And hopefully, new tools will emerge and prove useful in their own right and their niche.