I'm not going to bother with Swirlix because I think it's outrageously broken and everybody else has pretty much said everything already.
From my experience, Gligar suffers too much from 4 moveslot syndrome to be truly broken. Used defensively, it has great utility, but it can't carry Stealth Rock, Defog, Roost, Knock Off, and U-turn all at the same time. Offensively, it has the same problem. Earthquake, Acrobatics, and Knock Off might be perfect coverage, but then it only has one slot left. I think the most dangerous set is SD, Earthquake, Acrobatics, and BP, but even this I've never had a ton of trouble with. As long as you prevent a clean Baton Pass, you can revenge Gligar with a scarfer. Any other offensive set lacks something, whether it be coverage, power, or speed. (A caveat: I very frequently use Porygon AND Slowpoke)
So I'm a bit on the fence about Gligar. However, it is insanely centralizing. It's very difficult to justify not using it (I'm honestly surprised its usage is only 40%). There are tons of pokes that now carry Ice moves just for Gligar. And people are using particular scarfers just for Gligar.
In conclusion, my opinion:
1) Swirlix is broken
2) Swirlix is sort of making LC less fun
3) Swirlix is probably deterring people from LC
1) Gligar is not truly broken
2) Gligar is making LC less fun
3) Gligar is definitely deterring people from LC
From my experience, Gligar suffers too much from 4 moveslot syndrome to be truly broken. Used defensively, it has great utility, but it can't carry Stealth Rock, Defog, Roost, Knock Off, and U-turn all at the same time. Offensively, it has the same problem. Earthquake, Acrobatics, and Knock Off might be perfect coverage, but then it only has one slot left. I think the most dangerous set is SD, Earthquake, Acrobatics, and BP, but even this I've never had a ton of trouble with. As long as you prevent a clean Baton Pass, you can revenge Gligar with a scarfer. Any other offensive set lacks something, whether it be coverage, power, or speed. (A caveat: I very frequently use Porygon AND Slowpoke)
So I'm a bit on the fence about Gligar. However, it is insanely centralizing. It's very difficult to justify not using it (I'm honestly surprised its usage is only 40%). There are tons of pokes that now carry Ice moves just for Gligar. And people are using particular scarfers just for Gligar.
In conclusion, my opinion:
1) Swirlix is broken
2) Swirlix is sort of making LC less fun
3) Swirlix is probably deterring people from LC
1) Gligar is not truly broken
2) Gligar is making LC less fun
3) Gligar is definitely deterring people from LC