Double posting to share my thoughts on the new spotlight after building a few teams and playing some games in order to hopefully start a discussion on how to start balancing this with the AAA Ubers tour (
signup here) starting next week.
There's a few things that immediately jump out to me as metagame warping:

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Zacian-Crowned @ Rusted Sword
Ability: Tough Claws/Download/Steelworker
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Behemoth Blade
- Play Rough/Wild Charge
- Swords Dance
- Close Combat
Necrozma-Dusk-Mane @ Life Orb (or anything else, i chose LO for more power)
Ability: Regenerator
EVs: 248 HP / 64 Atk / 188 Def / 8 SpD
Adamant Nature
- Stealth Rock
- Swords Dance
- Sunsteel Strike
- Earthquake
Urshifu @ Choice Band
Ability: Sniper
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Wicked Blow
- U-turn
- Close Combat
- Sucker Punch
These two mons, or rather the simultaneous threat of both of them is a big pressure in builder. More immediately threatening is Urshifu, as nothing (yes, actually nothing) switches into CB Sniper Wicked Blow apart from max hp, max def Xern and perhaps mons running Shell armor/Shadow shield, the first being an insanely niche ability, while the latter is no longer a switchin after a U-turn. Realistically, this forces defensive xern onto teams, which can be taken advantage of insanely easily by powerful steel types such as Zac/NDM, especially as it's just barely not being 2hkod itself. These steels can be handled somewhat well by Hooh, opposing defensive NDM and in NDM's case Giratina, but this still forces you to run at least two physical walls to stand a chance vs a very strong and splashable offensive core. Zac additionally offers lategame cleanup and speed control as long as Caly is out of the way whereas the above EVs on NDM let it check Modest Tinted GeoXern by always living +2 moonblast from full as well as opposing Zac by always living +3 CC from Download or +2 CC from Tough Claws.
calcs (it obviously ohkos offensive stuff):
252 Atk Choice Band Sniper Urshifu Wicked Blow vs. 252 HP / 252+ Def Xerneas on a critical hit: 165-195 (36.1 - 42.7%) -- guaranteed 3HKO
252 Atk Choice Band Sniper Urshifu Wicked Blow vs. 248 HP / 8 Def Yveltal on a critical hit: 229-270 (50.3 - 59.3%) -- guaranteed 2HKO
252 Atk Choice Band Sniper Urshifu Wicked Blow vs. 252 HP / 252 Def Eternatus on a critical hit: 361-427 (74.5 - 88.2%) -- guaranteed 2HKO
The aforementioned defensive Xern set:

Xerneas @ Toxic Orb
Ability: Poison Heal
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Calm Mind
- Moonblast
- Defog
- Protect
While Yveltal could theoretically run physdef and serve as a switchin to Shifu+NDM, it is forced into running specially defensive regenvest in order to act as a switchin to the plethora of Ghost and Psychic type breakers, most notably Caly-S, Mewtwo and Lunala. Speaking of Caly S, the following set acts as the ultimate speed control against pretty much anything other than DD Ray, but TL/Adapt can also be used on dedicated Psyspam:
:calyrex-shadow-rider:
Calyrex-Shadow @ Choice Specs
Ability: Psychic Surge
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Astral Barrage
- Psyshock
- Expanding Force
- Trick

Yveltal @ Assault Vest
Ability: Regenerator
EVs: 248 HP / 8 Def / 252 SpD
Sassy Nature
IVs: 0 Spe
- U-turn
- Knock Off
- Oblivion Wing
- Sucker Punch
Moving onto Rayquaza, this is a mon that seems absolutely impossible to answer on paper, especially since there are no real defensive counters to it and DD lets it outpace offensive checks after one boost. Perhaps some versions of NDM can stomach hits from it and Prank Giratina can switch in on non Dragon moves, but that's about it. As for offensive checks, non DD sets are relatively easy to answer as long as you have a psychic surger on your team, whereas DD is only revenged by Sash mons or Scarf Dazzling Marshadow. With all that said, it has not been that impressive in practice but I also haven't seen much of it either.

Rayquaza @ Heavy-Duty Boots
Ability: Aerilate
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Extreme Speed
- Dragon Claw/Draco Meteor
- V-create/Earthquake
- Swords Dance/Dragon Dance
Rayquaza @ Heavy-Duty Boots
Ability: Tough Claws
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Dragon Ascent
- Dragon Claw
- V-create/Earthquake
- Dragon Dance
And last, we have the infamous Specs Ogre that claims a kill everytime it comes in:

Kyogre @ Choice Specs
Ability: Primordial Sea
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Water Spout
- Origin Pulse
- Ice Beam
- Toxic/Thunder/whatever, not like this clicks anything other than water stab
This is all for now. I am very interested to hear your guy's thoughts on this so feel free to reply or start a discussion in the PS room. We obviously won't be able to completely balance this, but I'd like to at least remove the elements that are massively constraining in teambuilder.