I wouldn't have reverted had the link appeared on
any page dealing
with the user in the context of a user, but the watchlist editor is
explicitly referring to the page, not the user. Ergo, it seems
completely inappropriate to me to arbitrarily change the semantics of
the context in which the title is being displayed for a single
namespace.
There is no need for the watchlist to just be a list of pages. It
could include anything watchable, including users.