Network was terrible for EX raid that started 90 min ago
Took each of our many groups 32 minutes to not error/freeze and then eventually win. Maybe they shifted a lot of network capacity to Chicago...or maybe a huge number of players decided to raid Regice and catch summer Pikachu all at the same time.
Personally, at least I can finally stop trying to get more Mewtwo. The 9 I've kept, recent to oldest

Answers
I didn't get my first 98% or better til Latias. Since then, 98% Kyogre, 100% Articuno, and this 98%. A typical city player average of 1.2 legendary raid victories a day. So higher IV RNG came around after 12 months in. Luck continued: born with focus blast and first charged TM it got Shadowball.
Maybe it is by design they aren't introducing a shiny Groudon or Rayquaza...it would overwhelm what might already be a network almost toppled. In this big city you'd have to taxi around all day and maybe only find 4 or 5 Regice you could even find people to help you battle against.