Well, for a good staller, you need to be able to stall(obviously)You'll need decent/average offensive power, and good defense(which Unfezant does not have without some major EV training in Defense and Sp. Defense) so I think you might be better of not using unfezant as a staller. If you want some good stallers, use speed freak's ideas under "Whats a good staller..." Black Haxorus asked this.
Hope I helped:)
P.S.To get to the question above, use the tag "stall"