Bit of a shame really since it would offer great synergy between the Warden's skills, but at the same time it might be too strong if it could be used on the Bear
"Stand strong, stay true and shelter all." Tryxus - Guardian of the Green - Warden - PC/EU
The act of being able to teleport to an NPC like that or other types had the possibility to be exploited and abused in Cyrodiil and so after it was reported it was changed to only work on Players.
I am surprised it is still not used in PVP at all (at least in zerg situations). The clockwork dlc changes made this gap closer (or more like creator) much faster and with ~40m range with cyrodiil buffs (before it was unaffected by all sitting at ~20m)