Should we double up on Legendaries this time around?

Seems there aren't many non-legendary pokemon that are as potent attackers like most of the legendary pokemon. As Legendary Pokemon can't be used to be placed at gyms, seems that's the non-legendary pokemon have the most upside in mainly being gym defenders. However getting legendaries just cost money. Now Niantic is recycling a past legendaries like Lugia to continue to bank roll with the premium raid pases. Should we double up or triple up on the same legendary pokemon?