Why can't legendarys be placed into gyms
This may be an old question but I still dont know it for sure.
What would speak in favor or against that to place one(and only one) legendary into a gym? This question came up since there are quite a few of defensive orientated legendary Pokemon. And its sad that they are barely of any use i think. I did read the poll from Pokemon GO Hub and thought that Niantic should do something about this.
Answers
Because people would stick Lugia and Ho-Oh in gyms to scare away Machamp, and the gym meta will change to spam Rock Ttar with Machamp swap ins for 3000+ CP Blissey. Plus, what legendaries can you name that are good at defending other than the two big birds?
Regis: No point putting them in gyms, as already made anti fat normal type Machamp battle parties will steamroll them.
The 3 Team Birds: No point. Tyranitar slays them easily.
Raikou: It'll be solid, but Machamp can still eat through it without much trouble.
Entei: Another reason to use Smack Down Ttar.
Suicuine: Same as Vaporeon, except it only tickles opponents. Hidden Power may offer some variety though.
Groudon: Good counter coverage, but probably won't fire off a Fire Blast or Solar Beam without getting dodged or killed first. At least it's not weak to Machamp, but when has that ever stopped Machamp spammers?
Kyogre: While having Blizzard to counter Grass types, it still falls to Raikou and the gang. Also doesn't have any counter coverage VS Machamp, in fact it resists Blizzard.
Rayquaza: Will get slaughtered by Rock Ttar, Ice types, and it's own kind. Nothing to see here. Dragonite is a better defender.
Mewtwo: Meh, while it resists Machamp it crumples VS neutral threats.
What you write is only halfway true. Raikou with Volt Switch would be an absolute pain to attack with Champ and surely chunk half life if you dont start dodging quick moves.
Regis would still be good picks, as their defensive stats are stellar. Their real drawback would be the one bar charge moves, that are ass. However they could give defender some more valuable time to notice an attack and feed golden berries.
Mewtu would be glassy but dish out a fuck ton of damage to Champ, so it could be placed between Chansey and Blissey very well.
Mew would be nice too, having a Champ resistance and great defensive moves. Imagine a Dragon Tail/Claw Mew, both Ray and Champ as premier generalist attacker would struggle and you would have to bring a 3rd attacker (Dark Ttar or SB Mew2) to deal with it effectively.
Kyogre with Waterfall could be an immense force on def too and would let Raikou shine again, as Waterfall and Blizz/Pump would be lethal, as its bulky enough to dish out a charge and has counter coverage with Blizz. Again, you might have to dodge the quicks with a Champ, if you dont wanna lose it too quickly.
Fighting does not resist ice.
Raikou at level 40 max motivation would take 25s to kill with Machamp and it would KO the Machamp if Wild Charges aren't dodged. Seems decent, much worse for Machamp than most other neutral matchups.
Like you write, none of them would be anywhere near broken, but many of them are bulky and would be better defenders than a number of defenders that are common in the current gym meta. Just having Lugia and Ho-Oh as alternatives would be great.
Articuno/Moltres: Smacked Down by Tyranitars very easily.
Zapdos: deals laughable damage to Golems, even with Thunderbolt.
Lugia: good defender, but careful attackers with Raikous can shock it.
Mewtwo: good Machamp killer, Confusion puts serious pains on attackers. Unlike Alakazam, it can release Focus Blast, killing Tyranitars if undodged (or at least take away 1/3 health). Shadow Ball versions are also very good, being less predictable. All 4 charged moves can be easily dodged, though.
Mew: extremely unpredictable, Machamp stopper. Volt Switch will be quite deadly, especially when carrying Ice Beam, Dragon Claw, Psyshock or Surf.
Raikou: there is Groudon. Mud Shot is good to dodge those Wild Charges.
Entei: Kyogre is here. Flamethrower can deal some damage back, though.
Suicune: Hidden Power can counter its counters. Bubble Beam hits often and Hydro Pump hits early. A solid defender, except against Alola Exeggutor unless carrying Ice HP.
Ho-oh: Smack Down Tyranitars don't have problems dodging that Solar Beam, too late damage window. Extrasensory does hurt Machamp.
Celebi: it needs better moves before getting eaten by that Pinsir.
Groudon: Kyogre is still here, charged moves are predictable. Not going to stop that Machamp. In Wind, Dragon Tail can kill frailer counters.
Kyogre: Raikou is here for Blizzard variants, Alola Exeggutor is here against HP and Thunder. Not going to stop that Machamp. In Rain, Waterfall hurts frailer counters.
Rayquaza: Articuno isn't going to have problems dodging AP. Outrage kills nearly everything if undodged. AA kills Machamps like crazy, very spammy. But it is somehow frail.
Latios: better Dragon Claw Dragonite, similar bulk/damage, better typing.
Latias: on par with Outrage Dragonite, trading damage with extra bulk.
Regice/Registeel/Regirock: USELESS, JUST USE MACHAMPS.
Deoxys: too frail, even with Machamp resistance. Tyranitar eats lunch, still not full.
Jirachi: Tyranitar will have problems against Doom Desire. Very good defender.
To prevent scaring newcomers. Having a Groudon inside a gym isn't the most friendly sight for a newcomer. By the way i suppose some legendaries can be put into gyms without scaring anyone, like Articuno and Latias. Those were legal in Battle Frontier or any Battle Format that restricts cover legendaries so i won't be any afraid if they were allowed as defenders.
There are couple of reasons for this decision, some say they are too OP (which proven to be false by the comments above me), some say they scare new-commers (which is stupid, isn't 3000CP Blissey not scary enough?), and more. IMO. there is no real reason why they shouldn't be in gyms, but I am not working at Niantic so...
