I would love to see how different a Gholdengo-less meta would be. It’s not broken individually but I think it represents the single biggest bottleneck to team building and playstyle development of any mon going back several generations. Every single team is prepped for hazard stack and the inability to defog. It’s no joke to say the entire meta orbits this thing in the builder both offensively and defensively. Basically I think its presence just makes the whole meta worse.
Here is a complete list of our potential defoggers:
Altaria - 70/70/80 offensively is abysmal, and it doesn't have enough tools outside defog viably run a defensive set.
Braviary - Too slow and frail
Braviary-H - Too slow and frail, its one (semi-)viable niche cannot fit defog
Corviknight - Already can run defog
Decidueye / Decidueye-H - Too slow, typing limits the potential of bulky sets, theoretical anti-meta option in the future
Drifblim - Has anti-Ursaluna niche, so if Ursaluna ever becomes a top tier threat, it'll do work; nonviable otherwise
Frosmoth - Viable on snow teams, potential option for defogging with Ninetails-A
Hawlucha - Can fit defog, cannot be a team's primary defogger due to team role
Kleavor - Can fit defog, cannot be a team's primary defogger due to team role; also bad in OU
Liligant-H - Has unexplored potential, though it really misses the lost coverage
Lurantis - Too slow and initially weak, nonviable in general and doubly so as a defogger
Noivern - Not quite powerful enough to hack it on OU, but might be Morkoal-able
Oricorio (All) - Too weak and frail
Scizor - Utility sets can run defog
Talonflame - Defensive sets can run defog, though it limits what they can check
That's it, that's the full list. There is not some massive list of potential defoggers that are being kept out of OU by Gholdengo; at most, it limits Corviknight and Scizor, both of whom are at least not free setup thanks to U-Turn. Offensive Gholdengo cannot safely switch into Liligant-H because it has a 75% chance to get 2HKO'd by a +1 Leaf Blade, though defensive sets only have to worry about taking a crit (which, with Leaf Blade's high crit rate, is a real concern). Tera-Ground Frosmoth is an OHKO, and can take a hit to pop an Air Balloon if needed - without needing to tera first unless the Gholdengo is specs, even. Talonflame 2HKOs non-defensive Gholdengo and 3HKOs a full defensive set.
There's also Maushold, who can use Tidy Up in front of Gholdengo and beats non-specs sets with +1 Bite.
The real problem is that most of those defoggers are either too weak to hack it in OU, or their team role doesn't allow them to serve as a primary hazard control role.