Actually if you look at the archives a bit, I've made a fairly detailed
outline of the features I intend to implement in my web based proposal
(under the "Nmap GUI" subject).
Now, my goal isn't to replace the role of a standalone GUI app in any
respect - this is a tool for people or institutions that routinely scan a
network over a long period of time and like to know what's listening on
which machines on their network, or when something new starts
listening...without having to keep tons of text/xml files around and
perform manual diffs of them. I'd contend that my goals would be MUCH more
easily implemented and utilized in a central, web-based environment than as
a standalone application.
I'd also contend that most people likely to deploy an application of this
nature would already have a web server running in some capacity somewhere
for internal purposes. The fact that the web server it runs on is
potentially vulnerable is also to an extent irrelevant for that reason.
Maintaining said web server would (hopefully) already be an exercised
practice. As far as the security aspect of the tool itself goes, such a
tool would ideally be deployed with proper precautions taken to isolate it
from unsafe networks and internal threats (behind appropriate firewalls,
access controlled, etc).