Legacy Moves
For those more familiar with the main series, is there any indication that legacy moves could return? One generation had it removed and the following brought it back? A special or move specific TM? Or some other means?
Answers
Correct. But like other people have already said, the legacy moves aren't related to the main series games in any way really... For example, scald is a legacy move already and that wasn't introduced until gen 5 in the main series. Also just to add on to my previous answer, there are cases where pokemon can't learn moves that they use to be able to learn in previous generations; but it's never because the moves have been completely removed from the game and then brought back later. So this means if you want a pokemon with an old, now unobtainable move, it will still be possible to use the move as it is still in the game. You will just have to transfer the pokemon with the move from an older game.
Legacy moves in PoGo don't have anything to do with movesets available in the main games. In those games, each mon can have up to 4 moves, and you can change them up at will using TMs and move tutors. Niantic seems to choose 2 fast and 3 charge moves from the available pool for a mon. So when Niantic made DB a legacy move, they simply removed it from their end. Dragonite can still learn DB in the main games.
That's not what the question is asking.
The question is asking whether there are Pokemon that learned a move in a certain generation, unlearned it, then learned it again.
For example, if it were the case Pidgey learns Tackle in Gen 1 but can't learn it in Gen 2, but is able to learn it in Gen 3, would that set a precedence for legacy moves returning in Pokemon Go.
Obviously removing a move from the Pokemon Go movepool has no effect on the main games when they were the ones that came first.
Ah, OK. The only one I know about is Salamence. It could learn Outrage in previous gens but can't anymore. I'm sure there are lots more. But Salamence losing Outrage was a bummer for me in Moon. I don't know of any moves that came back after being taken away. But it would be great if there is precedence for that.