Asuswrt isn't a full-fledged Linux environment, so it doesn't have PAM for authentication handling.
More advanced port forward edit options (editing/disabling) would be tricky. The disabling option would most likely break backward compatibility with Asus's original firmware (which I want to avoid), and the ability to edit them would require extensive rework to the HTML pages, which would make it quite complex to update to newer versions of Asu's code. I'm not ruling it out entirely for sometime in the future, but as long Asus makes regular FW releases, I want to minimize the work involved in merging newer code into the project.
Asuswrt-Merlin: Customized firmware for Asus routers
Github: github.com/RMerl - Twitter: RMerlinDev
See the sticky post for more info.