I have played with all 3 major pet classes [bst. mage, necro] and I can't help but feel the pets, themselves, are too weak - especially at 70 when facing seb+ stuffs.
Now players can get lots of chaotic gear, and weapons in the guk tier to increase their overall durability, and with aa's it might even be possible to solo much of the seb+ content. This is the greatest benefit to tank classes who pop a cleric bot and go nuts.
However, casters and bsts are lost at this point. I have seen a lvl 70 earth pet devoured by greens in seb and completely unable to tank 3 adds. Now, I am sure someone, somewhere is gonna say pets shouldn't be able to tank. But the earth pet is the mage's only defense and the only way a mage can nuke safely. Without a sustaintal ac or hp adjustment mage pets are next to useless outside a group context which severely limits the progression of people who play mages.
For bsts, the pet takes up roughly 1/3rd of their dps and I find the pets much more balanced. They still have problems tanking named in the seb+ and should last a bit longer, and again, when faced with multiple greens, they fold quickly.
I haven't played with necro's much, but indoors, without kiting their pets fold as fast as the mages.
I see the problem as a dicotomy of sorts. You don't want to increase the pets natural (via summoning) because the pet player would automatically be granted an upgraded pet without any real work but in addition, the pets even after the intial adjustment would just fall behind again.
My suggestion is 2 fold.
1) introduce upgrade augments in the guk tier. Possibly one for hp, for for dmg, one for spell procs.
2) Increase the benefit of augs for pets
3) and finally, perhaps put into place an epic question for pets. The reward could be a pouch that summons weapons that give complimentary procs (for mages for example, a malo sword and a 2k nuke as their epic) and you could even have the player specialize their pets via choice in epic quests. Examples,
Mage:fire [malo/nuke ac:low hp: low mana:high ds:high]
Mage:water [slow/ice ac:med hp:med mana:med aura:sloth]
Mage:air [whirl/stun ac:high hp:low mana:low aura:regen]
Mage:earth [root/ae earthquake ac:high hp:high mana:low ds:low]
Necro:SK [shrouds/high taps ac:high hp:med mana:med]
Necro:War [stun/hate proc ac: high hp: high mana:none]
Necro monk: [Dot (dragonfist)/enfeeblement] ac: med hp: med]
Necro: rogue: [poison proc ac:med hp: low]
Bst:WAR focus [root/stun hp: high ac: high]
Bst:Utility focus [slow/snare hp:med ac:med]
Bst:Proc Focus [% increase to magic procs, ac:low hp:low]
You could call the items totems for mages, jewelled skullls of X for necro's and fetishes for mages or something.
Would be interesting to make pets for viable and give pet classes a clear path for upgrades regarding their pets without handing them free upgrades.