I think it would be nice as a purely aesthetic feature to make it so when more than one arrow is in an inventory or dropped on the ground, for it to use the quiver sprite. Also to put a quiver on the players back when they are using a bow. The quiver can also fill up more depending on how many arrows are in a stack.
I think the reason it is not in the game anymore and probably never will be is for two reasons: as Jeb said in the wiki page, arrows in the off-hand felt more natural. Therefore, when they add the off-hand thing to CE, they won't have quivers. My second reason is because I believe (I think I heard this somewhere) Notch removed it because there was lots of negative feedback on it. Not about bugs, just that it was unnecessary.
You dont carry a quiver though, it gets slung over your shoulder and is on back.
As the OP mentioned, it could be purely aesthetic, tho would be better to have additional values.