It depends on the warde build. Which can be a total mess.
Some warden take melee build, that use a lot of rubie and not enough for pet.
Other can take healer + caster build: not enough rubie for pet.
Some can take full pet rubies: there is your pain.
Pet deals good dmg, only if used with casting combos. That will use all rubies, not enough for decent heals and no melee rubies.
Is like the summy has Acid or Vamp build, just at ardens are 2-4 combined builds, not so distingushed as at healers the Caster, melee, healer.
It is't like the Hellion: just spell and no rubies and no spell rotation required.
It require spells + rubies and spells rotations.
So you can't say the pet deals huge dmg or not, depends on warden build.
+ patches are nerfing / buffing the spells. At 5.0.0 it was an OP caster => warden did the most dmg not the pet.
Now at 5.0.2 nerfed the casting and the heals and so on => many took melee or pet dmg.
There is a green head debuff on you ( Pain shock) It is the same icon what you can see at AoD.
-if you see that: just CC the pet and don't allow to touch you, because high dmg is coming.
When the pet has a yellow/orange/red pet footprint buff, then he deals more dmg, then normal: must CC the pet ( or kill )