We don’t know the extent of the Chantodo nerf yet. It probably won’t be that much. If they reduce Chantodo’s damage to x5 instead of x6, it’s probably what…5 GRs or so? Someone with a better idea of the math could chime in.
Honestly, Chantodo’s doing 96% of the set damage was pretty ridic - I hope they up the damage of Archon abilities as a band aid.
1/2 damage = 4.4 GRs.
ln(1/2)/ln(1.17) = -4.4
If they remove the attack speed scalar entirely, so 5x to 1x = 1/5 damage, it’s a 10.25 GR damage loss:
ln(1/5)/ln(1.17) = -10.25
I haven’t been on PTR yet, was busy yesterday. Will check it out this weekend. But from Cratic’s post on PTR feedback, sounds like it’s somwhere in the ballpark of 1/2 damage compared to live. Give or take.
My 3 wishlist sets:
With supporting legendary offset items.
Does anybody use that Black Hole belt anyway?
The belt needs to give a damage boost to blackhole; of course that won’t be enough. Blackhole needs a few more legendary items, otherwise it’d face the similar issues that the foh set had during the ptr.
Of course, I hope we don’t get a set that’s only for one or two skills, but looking at how the monk and crusader set operated (although that was ptr), I can’t see myself expecting more.
Another one for Hydra 
There are already a few legendary items that provide buffs and benefits to Hydra, but no set - yet - tying it all together, and in a game where (with the exception of LoD/LoN builds) we are otherwise forced to use sets, this presents something of a problem. However, it also means that, at least hypothetically, Blizzard has a lot of raw material to work with in order to create a new set for Wizards that can synergise with currently existing legendary items. I just hope that they don’t make the same mistake they did with the new Crusader set, where supplementary items were either not added, or existing synergistic items weren’t buffed adequately to make the build competitive 
I would like to see Explosive Blast, Blizzard, Disintegrate, Black Hole, Wave of Force, Arcane Torrent usable as main damage skills. I don’t personally have any interest in Hydras or Mirror Images though I can see I am in a minority on that.
I would also like to see Twister made playable on PC again. A Firebird’s and DMO rework that didn’t feel awful to play. A Tal’s rework that didn’t eat 4 of your 6 skill slots to maintain the set bonuses. Archon builds where Archon abilities actually dealt some meaningful amount of damage, even if only to proc MH again.
Honestly, for how strong the top 2 Wizard builds are, most everything else for the class is either outrageously underpowered or unpleasant to play.
The most important thing it has to feel smooth and not clunky. With the new crusader set they did probably a good job. About the Monk set unsure.
I agree; hopefully they also consider adding more legendary powers for whichever skills they plan on making the set for.
They updated/adjusted about 11 legendary powers with this patch. And with WC3 Reforged beeing about to be shipped and D4 in the works. They will probably put more classic team power into D3. And only if it’s because to promote D4 and have a more active userbase in D3.
Perhaps, but those were mostly barbarian items (which of course were long overdue); I’m just hoping we don’t get a similar situation with the crusader set, whereas only one skill is buffed and that skill only has about one or two support legendaries.
I would kill for a wizard set like that. Sure, only two skills, but, two thematically consistent skills, lots of build combinations and t16 play style combinations (see blizzcon set update) - further more, none of fuc*king clunkiness and broken mechanics of wizard sets.
The problem with a new set for wizard is that all the damage has to be in the set itself. If they add a new set and then give extra legendary power buffs I can almost guarantee you a Tals or Vyrs variant will be better.
(2) Set:
Chance when attacking to summon a Mirror Image (there is no longer a push effect, when summoning a Mirror Image!) behind your target that casts some of your equipped skills and taunts nearby enemies. Mirror Images can not be killed and each lasts for 22 seconds. When you or your Mirror Images deal damage, there is a chance that the remaining time of the Mirror Images will be reset by 2 seconds (so that they last longer). Spells cast by your Mirror Images will deal 33% of the damage of your own spells.
You can have up to 6 Mirror Images at the same time.
(4) Set:
Decreases the Cooldown of Teleport by 66%.
For 11 seconds after you Teleport, you will take 55% less damage and your movement speed is increased by 66%.
(6) Set:
For 11 seconds after you Teleport, your damage is increased by 9999%.
.
With these legendary items you can use Magic Missile or Piercing Orb as Main-Skill, very similar to the Crusaders Captain-America-Build:
Hounted Missiles
1-Handed-Wand
Magic Missile now deals 666% weapon damage, becomes a Seeker, searching for targets, and has a high chance to bounce between targets.
Hounted Orb
1-Handed-Wand
Piercing Orb now deals 666% weapon damage, moves forward in a straight line, searches for enemies and bounce between targets.
Supercharged Orb
Piercing Orbs deals 333% increased damage to the first target, hit.
There’s a chance, that Piercing Orb electrocutes enemies for 333% weapon damage as Lightning along its path, in a wide area.
.
Explosive Staff
2-Handed-Staff
Increases your damage by 666%.
Damaging enemies with Arcane, Cold, Fire or Lightning has a very high chance to trigger an Explosion of the same damage type on hit, at the target location. Explosion immediately deals 1111% weapon damage as Arcane, Cold, Fire or Lightning to all enemies within 15 yards.
This also works for proc skills like Familiar, Hydra and Mirror Images, and Ice Armor, Storm Armor and Magic Weapon.
With this set and these legendary items you can use Hydra now similar to the Traps of the Assassin:
(2) Set:
Hydra now summons an Hydra that consists of the 4 Elements Arcane, Cold, Fire and Lightning with 4 different heads (Arcane, Cold, Fire and Lightning). The Hydra attacks enemies with bolts of Arcane, Cold, Fire and Lightning each dealing 666 weapon damage as Arcane, Cold, Fire and Lightning. These bolts of Arcane, Cold, Fire and Lightning have a chance to bounce between targets.
Hydra lasts 22 seconds.
You may have 5 extra Hydras active at a time.
(4) Set:
Each active Hydra reduces your damage taken by 10% each and increases your movement speed by 10% each.
(6) Set:
Each active Hydra increases your damage by 1500% each.
.
Explosive Staff
2-Handed-Staff
Increases your damage by 666%.
Damaging enemies with Arcane, Cold, Fire or Lightning has a very high chance to trigger an Explosion of the same damage type on hit, at the target location. Explosion immediately deals 1111% weapon damage as Arcane, Cold, Fire or Lightning to all enemies within 15 yards.
This also works for proc skills like Familiar, Hydra and Mirror Images, and Ice Armor, Storm Armor and Magic Weapon.
Serpent’s Orb
Orb
When you or your Hydras deal damage, there is a chance that the remaining time of your active Hydras will be reset by 1 second (so that the Hydra last longer).
The Magistrate
Hat
Hydra now periodically pull in enemies.
Serpent’s Sparker
1-Handed Wand
You may have 1 extra Hydra active at a time.
Please also take a look at this:
A few thoughts, the 2 piece is garbage. Mirror images count for a negligible amount of damage. What you want is for YOU to do 33% more damage for every mirror image. 10k damage probably won’t be enough to be viable. We’d probably have to up the to 15k. Other then that, it’s a fluid, open set (perhaps too open.) that would be enjoyable.
Also worth remembering is Archmage’s Vicalyke is a thing. Ideally, it would be designed to complement this set, such as “Mirror Images spells do 50% of your damage.” or “Mirror images now cannot be killed.” and integrate that into the set in a way.
Also, I think we can summarize your “Two Handed Staff” legendary as WAY TOO GOOD Full stop 
Even a 666% multiplier is insane and completely off the table, nevermind any additional affix. Furnace sees uses at 50%.
You can, however, do 600% damage to a specific skill, such as Slorak’s increasing Disintegrate damage by 600%, a needed an necessary change.
If you want to increase Primary skill damage, there is already an item for that. Just up THAT affix.
Honestly, fixing D3 itemization isn't that hard. The hard part is the coding, and the time it would take to fix the really bad job previous developers did. It's far too late now - not enough resources. all we can hope for is specific, targeted fixes.
Having 7 Hydras would absolutely MELT the servers. There is discussion whether the game could even handle three hydras. You could probably get around this by having Hydra increase damage by ~3500%, for a total of ~10500%
Because of this, you would have to redesign your 2 and 4 piece. My suggestion? Your Hydras also do X% damage to nearby enemies; or "You hydras also cast your Arcane power spells. " and an attached duration increase. The 4 piece with some kind of DR mechanic. You gain 20% DR for every active Hydra, assuming you’d have three, would be sufficient.
Don’t lose sight of the goal, you want a fluid, functional, themed set in most cases. Another idea thrown around a lot is a blizzard + hydra interaction, like “Enemies damaged by Blizzard take X% more damage from Hydras.”
Would love to see a set that does something fun with Blizzard and Hydras.