I cannot object something that you want to do personally. Naturally, you are fit to do whatever you wish with the code, that's why it is open source. The Core Team does not encourage branching, but there's nothing stopping you from doing it.
A few things to keep in mind:
- Before branching re-read the documentation that applies to usage rights of DNN brands.
- Make plans to provide yourself resources needed to those that will use the version you start. These resources include: support forums, download location, release and development information and so forth.
- Stablish a method to implement future functionality, unless you are happy with current features plus the one you plan to add.
You see, I said personally because that's my opinion and to use your wording I chose not to be useful in a way that pleases you but rather than allowing people that do not want to or can not branch. Now go ahead and be as useful as you want.