The State of Legendary Raids
Curiosity struck me, and was just wondering what do you guys think will become of legendary raids once quests are officially in the game? From the link I read from Detonatress's post, legendary Pokémon can be encountered by achieving a Research Breakthrough from getting seven consecutive stamps through daily quests (better idea for legendary Pokémon than raids, in my opinion). I'm assuming these legendary Pokémon will be those that we have encountered in the past already and they will appear randomly.
What if this also includes legendaries that are new? For instance, if Latias/Latios are released after April 2nd, will they appear through T5 raids, the quest system, or both? Would T5 raids even be necessary if there is an alternative way of acquiring legendaries? I personally think it should just be removed, if that's the case. Mewtwo is an exception, though, since it is distinctively obtainable through EX Raids only, so I can buy that. If they have the newly released legendaries in T5 raids and the old ones in the quest system, I guess that could work, too.
Answers
I imagine there will still be demand for legendary raids once quests come out. Completing a quest will take at least a week and it sounds like you'll get a single encounter after that quest is complete. Raiding will give players in high density areas the chance to acquire legendaries and candy at a much higher rate, while the quest system will provide an opportunity to catch legendaries on their own.
It doesn't seem like achieving Research Breakthroughs will guarantee a legendary encounter. Niantic stated we may even encounter a legendary Pokémon, so it'll be possible to encounter one, but I imagine it will be a very rare encounter, which I am fine with. Their appearances will most likely be dependent on the level of difficulty of the quests completed.
I was thinking on this as well, but I actually think that the old raid system will continue cycling the Raid Bosses we've seen while the quests will lead to the newer ones.
The reason I was thinking this is because the Regis won't be as big a catch as the originals (could be duoed?) and Lugia shows that the addition of a shiny make the existing Legendary Raids popular.
Except that the material the YouTubers specifically states that there are both Mythical and Legendary encounters in these quests. TrainerTips, who had a meeting about this a few days ago, with Niantic, said that it was a way for rural players to get Legendaries without having to do the 5 star raids.