Have they nerfed it? Seems like it never finds anything useful but Roar/Bloodlust/Fireball.
For example (only one example) today my opponent had multiple Zilliax with reborn on board, I had board full of small minions with 1 or 2 attack. Opponent had maybe 18hp. I Zephrys and it gives me either Holy Nova, Avenging Wrath or Tirion. No silences or Poly/Hex? Also, I swear I’ve never seen Fan of Knives from Zephrys. 
I am not sure how polimorph could be useful in this situation
Well it could transform Zilliax with reborn to a much less harmful minion.
You had 10 mana to start?
Zephyrs was trying to resolve it with one card, otherwise, a poly would leave the rest of the board filled with reborn Zilliax. Poly would only resolve one of those zilliax.
I don’t think there is an answer for this other than plague of death, which costs 9.
There is no other single card answer to that.
But there are more than one Zilliax, Tyrion can force them to attack it and die, so you could snipe them with your little minions
I think this is one of those times when you just pick what is best because zephyrs doesn’t know what you have in your hands.
Tirion isn’t a bad answer. It gives you a 5/2 weapon that can help clean up or finish off and, unless the opponent has hard removal, he’s quite wall to get around
I had 8 mana at round start, I forgot to mention.
Situation was something like this
Priest
3/1 Zil Zil
My side bunch of lackeys
Rogue
Zephrys finds only from basic and classic sets, but Holy Nova is not good against divine shield. Neither is Avenging Wrath good for reborn. What was Zephrys thinking?
edit: I may have had 10 mana, not sure and I don’t have a record to show.
from what i understand, zephrys assumes you want either kill you opponent (which you couldn’t have done with silence since you had only 1/1s on board) remove as much stat of your opponent’s ‘current’ board as possible (which, again, silence takes away no stats and poly only 2/1 worth) or develop board presence (tyrion)
zephrys doesn’t ‘predict’ super well, yes, killing the two zilliax with holy nova essentially just result in two 3/1 zilliax (assuming you trade your lackeys fir ds) but from its pov, you still removed 9/5 worth of stats from the board in one spell.
I mean in a spot where Mass despell would result in a bunch of 3/2 vanilla and give you a card and save you a Mana while Holly Nova should result in Devine shielded zeliaxes with taunt and lifesteal zephris should always give despell.
Zephris was never great at reading double boards but at times it does seem like blizzard made him more stupid than he should be in perpose.
another possibily is that zephrys understands the following:
this 3/2 minion has divine shield. it therefore needs to be attacked twice before dying
this 3/2 minion has reborn. it will come back with only 1 life after death. it will thus need to be attacked twice before being completely removed.
what I think he doesn’t ‘get’ is that zilliax will reborn with a brand new divine shield and thus needs 4 attacks each to fully be gone
assuming you have 4 lackeys, mass dispel lets you clear the zilliaxs (mass dispel, bump bumpx2) but since he’s no thinking of the reborn divine shield, so does holy nova (bump×2, nova, bump×2) plus it killed the 3/1
Rarely, does Zephrys offer me something that isn’t what I need. Once in a great while he does, but not often. You need a good understanding of what cards he can generate, and play down to the exact mana needed for that spell, after you play zeph. For instance, if windfury gives me lethal, I’m not gonna drop zeph with 10 mana, cause he won’t give me windfury. I play down as close to four mana as possible, play zeph, and get my 2 mana wf.
I did.
Also, sometimes, there are no card that can save you in the Zephrys pool. You have to tweak things a little before playing the card.
Mass Dispel certainly isn’t ranked by Zephrys at the level it should. As the ultimate “screw you!”-card, it should definitely have a bigger weight.
Also, Fan of Knives indeed seems to be incredibly hard to get. I once played Zeph when my opponent had a bunch of 1 health stuff and I had 5 mana, meaning I was down to 3 mana when I played Zeph: I was offered Arcane Explosion, but not Fan of Knives, despite having a very healthy deck and no 1 mana stuff. ??? ???