Hi there as we all currently facing the problem Server crash and it is very annoying when it happens during Boss Battle, Safarizone,Bug Catching and rarest case is while encountering shiny or Event poke. To deal with this I have a idea but not sure if it is possible.
It should be like it saves the game data on device the player is using and when servers comes back it saves all the progress on the main online servers i.e Silver/Gold.
During Offline mode player can't interact With other players but can do all other stuffs just like a regular pokemon game.