I was just curious why legendary pokemon can't be caught. It takes some of the fun out of the game. Would it be possible to make it so people could catch all the legendries but ban them from pvp and events so that people can still enjoy those aspects of the game? Maybe add in a little popup before doing boss battles or events that says "You can't do this event with any legendary or mythical pokemon in your party". I think that would be a fun way to add them in.
P.S. I'm not sure if this mechanic is because of the rather game braking nature of legendries or if it's a coding issue. Sorry if I overstep.