State of the Metagame Address
With the recent massive surge in interest for the Let's Go format (95 players on Nexus holy shit lmao), we have been able to collect a surplus of replays and opinions on the metagame. All kinds of developments have occurred during the past day alone, and while there is still some uncharted territory to be explored, we can begin to draw conclusions already.
The Champions
To start off with, let's take a look at the leading Pokemon of the metagame.
Out of all the things players believed would come to dominate the metagame to a borderline unhealthy extent, I don't think anyone expected Eevee would fall into that category. But here we are anyway. Eevee is the definitive best Pokemon in Let's Go OU. This can be attributed to its whopping total of
9 new signature moves, 8 representing the Eeveelutions, and the 9th being Veevee Volley, a Return clone. Not only to these moves provide it with incredible coverage that almost everything else envies, but each of them come packed with bundles of utility, from Baddy Bad setting reflect, to Freezy Freeze Hazing away opponents' stat boosts. But out of these moves, the most dangerous by far are Sizzly Slide and Sappy Seed, the former being a 90 BP special Fire move with a 100% Burn rate, and the latter being a 90 BP physical Grass move which applies Leech Seed on the foe. Combined with Substitute and Eevee's serviceable boosted stats, these moves make Eevee able to whittle down and cripple many threats while keeping itself healthy. It can mix and match its moves to serve any role it wants from cleric to screens setter to status spreader, it's just so good; if any Pokemon is to get banned or restricted somehow, it'll be Eevee almost for sure.
If Eevee is the king of Let's Go OU, Mew is the prince. Mew does much the same as it has always done, more specifically messing up foes with it's extremely versatile stats and movepool. In Let's Go, Mew's iconic defensive set is semi-intact with Will-O-Wisp and Roost, and it can also opt to serve a role as a potent breaker with Nasty Plot or even Bulk Up. Mew has tons of sets, and all of them can mess you up if you're not careful.
Venomoth is one of only 2 Quiver Dancers in the game along with Butterfree, and by far the most dangerous one. After just one or two rounds of set-up, it can clear through teams with Bug Buzz and coverage like Psychic and Sludge Bomb, all the while taking advantage of the high bulk granted to it via LG's candy mechanics via Roost. Oh, by the way, it gets Sleep Powder too, so even its checks aren't completely safe!
Muk-Alola, even by LG standards, is an amazing tank and blanket check. Its impeccable defensive typing means that you'll rarely be hitting it very hard at all, and it has a wide host of moves to attack with like Poison Jab and Crunch, or to annoy and support its team with like Haze, Taunt and the ubiquitous Rest, which it can put to especially good use.
And finally, at the lowest end of my personal Top 5 is the Let's Go games' only new fully-evolved Pokemon, Melmetal. Much like Muk-Alola, it serves as a tank that takes advantage of its amazing defensive typing and bulk to sponge up hits effectively. Unlike Muk-Alola however, it hits much harder, sporting EdgeQuake coverage and its signature move, Double Iron Bash, along with a gigantic 143 Attack. The flinch chance on this attack may seem redundant in conjunction with its low speed, but this is patched up with its access to Thunder Wave, which allows it to take advantage of a deadly ParaFlinch combo in the vein of Jirachi.
Rising Stars
These Pokemon, while not the best of the best, have been growing in popularity and usage.
Exeggutor is back, and it has some cool new toys. Not only is its typing once again helpful in a meta with few Bugs and Ghosts and plenty of Psychic, Grass, Rock and Electric type mons and moves, but it also has the incredibly annoying combo of Sleep Powder and Teleport, which, for the unaware, is now a -6 non-damaging move that switches out the user. Even the mighty Venomoth has to fear switching in due to Psychic.
Golbat is an interesting defensive threat. While it has lost Defog access, it retains Roost, can phase with Whirlwind, and is one of the few Pokemon who can fit U-turn onto their moveset. What it lacks in power is made up for in bulk and utility.
In a meta where Eevee and Melmetal lurk at every corner, Machamp finds a niche with its Bulk Up Rest set, which can easily dismantle these key threats and more with Brick Break and coverage such as Rock Slide.
The Unexplored
These are Pokemon I have used that I think have frightening potential, but just don't get the usage to back my claims for some reason.
(Mega)
Most people look at Mega Pinsir's lack of Flying STAB and 4x Rock weakness and automatically discard it as bad. That couldn't be further from the truth. As a matter of fact, Mega Pinsir is one of the most deadly and severely underprepared for sweepers and wincons in the entire meta. The rocks weakness isn't a terrible problem considering Pinsir's high bulk and only 2x weakness pre-mega, still allowing it to set up with a Sub Bulk Up Set before Resting all the damage off and striking back with X-Scissor. You don't even need to run Ground coverage; Melmetal lacking Rest straight up loses to Sub Bulk Up by virtue of Pinsir's impenetrable physical bulk after set-up. Even the mighty Eevee is destined for failure if Pinsir gets up a Substitute in time. And it can do this quite handily by virtue of its great 105 speed tier, something Machamp cannot claim to have.
LGPE doesn't have many Swords Dance breakers, the most notable of which is Dodrio. However, one that many overlook is Kabutops. Unlike Dodrio, it has access to priority and Superpower to easily one-shot Eevee at +2, as well as higher defense, and unlike Rhydon it has strong water coverage, Swords Dance and a very potent speed tier.
Picture Golbat with higher bulk but a worse typing and actual offensive presence, and you've got a good summary of how Articuno functions. The 4x rocks weakness may seem like a downer, but Articuno's so bulky it barely matters, you'll almost always take a hit even after Rocks and be able to Roost it off.
Before we go...
I want to deliver a message to everyone: This message is a good part of the reason I made this post at all. I know this meta looks extremely backwards and stupid; you are not wrong to think that. This meta is indeed way slower and has more jank strats than the main USM meta. But don't be intimidated by the insanely high average bulk of the format and the grand total of 1 viable Pokemon that isn't part of the original 151. Because when you look past that, what you'll find is an experience unlike anything else, and I mean that in a good way, honest to god. Lemme put it this way: The people who are complaining the most about LGPE have barely played a single game. I committed that same fallacy too, but I gave it more of a chance, and now I'm having lots of fun with it. The actual games will probably still suck, but the competitive metagame, as surprising as it may seem, ain't that bad.