So, the Master Ball is now a thing in Pokemon GO, but I hate to say this, it's kind of pointless.
Can't use it in Raid Battles for Legendary or Mega Pokemon since you can only use Premier Balls.
Legendary and Mythical Pokemon don't spawn in the wild (the Galar Birds have been the exception but that's usually been through incense in my experience).
We no longer get Legendaries through weekly/monthly research breakthroughs, and everything else that spawns is not worth wasting a Master Ball on.
Not to mention, when you do Research for a Mythical Pokemon, you don't get the option to switch from Poke Balls to Great or Ultra Balls, and you would have to burn through ALL OF THEM (depending on how many you have of any of those) before getting to your ONLY Master Ball.
Also, what Legendary/Mythical is when you only use ONE Master Ball? I remember in the First Gen games, Mewtwo could only be caught with a Master Ball, but you could catch him with a Poke, Great, or Ultra Ball with berries...
and if you did a nice, great or excellent throw (and even as a curveball in any one of those catagories).
Long story short, the Master Ball is pointless, and I doubt will ever get more than one, as I can't see the glitch from Red and Blue versions (or Red and Green in Japan) ever being put into the game to clone the Master Ball. Not like it matters much because all Pokemon in game are available to all players, but I get that want the game to be more challenging for the experience but still...
Just seems the Master Ball is a little pointless unless you want to use it on a Legendary/Mythical Pokemon you really want to catch.
Probably Arceus would be the one I would most like to catch with it, but of course, another downside is if you miss a throw or the Pokemon deflects it, then the Master Ball is gone... FOREVER! Or, it's gone until Pokemon GO decides to bring it back for another set of research (if they do).
Anyways, that's my two cents. Not the worse update, but just pointless.
RevHellCowboy