As a lugia advocate, I think it'd be a great asset for ndou. Its defensive utility and it being the only good defogger is something that the tier desperately needs at this time. Its bulk allows it to check two of the biggest threats(zama and waterpon) while not being passive with calm mind which is a huge plus. While this might mean that it'd be hard to check, you'd be wrong. There are many mons to check it such as weavile, darkrai, mban, boulder, crown, kyurem, etc. And if lugia teras, that's even better! This means that you can check it with your other mons like gouging, bolt, scarf lele, tera steel zama, karp, pod, etc. Overall, I think lugia would be a good and healthy presence for the meta and if it ever got suspect tested(which it should), I'd personally vote Unban.