In Inception, Cobb's totem was a spinning top, that in reality would stop spinning eventually.
Arthur's totem was a special dice, that in reality would roll a particular number more often.
Ariadne's totem seems too simplistic for that purpose... a chess piece (bishop) that she knocks over.
I realize she drills a little into it, possibly making it lighter or changing the center of gravity to make it easier to knock over... but that seems too simplistic... a projection or another person in her dream could easily replace that totem that she would knock over, and it still goes over...
It seems to me that in order to work properly as a totem, it would change state in only a way you would know to expect as validation of YOUR dream or someone else's dream. Whereas Cobb's totem's action is only known to him/Mal and Arthur's totem's special feature is only known to Arthur as well, Ariadne's totem seem too easy to copy by another architect. Why does it work as a proper totem?