I also have a feeling people dont realy like the mewtwo raid.
When i am hosting, sometimes nobody shows up, or it takes the whole clock for a full team, or the whole clock, and then have to quit, because i dont have a full team.
Guys Mewtwo isn't that hard. He just needs a better strategy than trying to just kill him quickly.
Easiest way to do it is to coordinate grimmsnarls/whimsicott. When his shield is down, taunt, multiple confides to drop special attack (grimmsnarl) or charm (whimsicott). Add in thunder wave, light screen/reflect (depending on what attacks mewtwo is using, he will either be a sp attack or attack, but won't mix). Get him down to almost nothing first with prankster ability pokemon and you are set. The worst thing people do is just try to constantly attack through him. When your health drops below 50%, heal the mon. Its a longer game, you aren't going to just attack him down. When he is down to minimal effectivenes, then just sweep through the first shield, reset everything, sorted. And DEFINITELY have lvl 100 fully trained (both IV and EV) pokemon.
So in saying that, I need another 2 grimmsnarls to coordinate attacks for mewtwo. If played right, we could harvest ALOT of stuff. Reply to this comment and I will send my details.