Hrm. I think it's a clever use for the macro, but I feel like the benefits really aren't that great. Changing 1000 instances of "X" to "Y" isn't hard at all (for most purposes) -- you just throw it through
sed and that'll take care of everything.
Also, how does {{PAGENAME}} behave with a redirect, I wonder.
EDIT: Looks like it
handles redirects fine, if anyone was wondering
EDIT2: Also, you know. If they change names, we're going to have to go through a bunch of pages anyway and correct it, since a bunch of pages refer to "Malcolm" other than the main article. If you really wanted to devise such a system, you could make a template for each name which can change, and substitute that in everywhere (please don't). Doing that would be overkill I think D:
EDIT3: I just saw your comments on
Category talk:Monsters, and have to say I think using {{PAGENAME}} to refer to images (ie [[Image:{{PAGENAME}}.gif]]) is a terrible idea -- it imposes restrictions on both the file format and the naming convention which I think are unnecessary. If you want to put an image in the template, just use a named parameter or something :x