For regular HTML and XHTML pages (i.e. like those used by Facelets) it would be
great if NB offered an "Open With..." type of option where you could register
external WYSIWYG HTML editors, e.g. NVu:
http://www.nvu.com/index.php
or DreamWeaver and automatically edit those pages in a WYSIWYG environment
(since Facelets supports this via component aliasing, i.e.the "jsfc" attribute").

Presumably, the developer would still spend most of the time in NB (due to code
completion support, etc.), but presumably every now and then he would want to
switch to a WYSIWYG editor just to work on the general layout of the page
(especially when creating template pages for Facelets).

Visual Studio.Net has a similar feature where you can define multiple programs
(including external oens) with which you can open any type of file, with one
being flagged as the default one when the user just clicks on a file.

P.S. It would be also great (if possible) to split the Facelets editor into a
"Preview" and "Source" view, so that they could view the page (if developed
using component aliasing) in an embedded browser via JDIC (or at least offer a
Preview toolbar item that would open an external browser window with a preview
of the page, similar to what Matisse does for previewing forms and panels).

P.S.S. Once the Visual Web Pack is integrated, adding an actual WYSIWYG editor
for Facelets right into NB would be great too, but I realize this is a much
bigger undertaking.