I think they've really bungled mewtwo raids. When they were released in Japan, the hype was real. YouTube videos were getting the kind of views they haven't gotten since last year. People at raids were all talking about it and trying to do as many raids as they could to increase their chance and then....nothing. A few people got them seemingly random and then you never heard of any again. Now they announce they are going to redo the system, but they won't recapture the hype they had before.
Raiding has slowed down significantly and this Halloween event has fizzled since it takes about an hour to get all of the new mons and then what's the point? Trying in vain for a shiny I guess might keep some going. If you need gen 1/2 candy, too bad because there are about 6-8 mons that have taken over your encounters.