There was a whole bunch of years there between Bird and Pierce where I thought it really dumb for there to have been a team captain.
We might be entering another phase of Celtic lore where maybe its best not to have a team captain rather than having marginal players like Rick Fox, Dee Brown, Dana Barros, Pervis Ellison and Antoine Walker be captains.
If a couple years from now Rondo or Sully or someone else has proven he is an all-time Celtic great and is a proven leader, then sure, make them captain. Until then, do the Celtics really need to give out that title?