"What is the hardest Legendary raid boss released to date, or projected to be released? Are there any that cannot be done with four people now?"

#PokemonGO: Specifically asking because I'm curious if my group of four can theoretically defeat any Tier 5 or Ex boss, now that the changes to typing has made raids easier across the board.Are there any Legendary bosses, known or projected, which are too difficult to be taken down by a group of four with appropriate counters (assuming teams of level 30, non-legendary counters with the correct movesets)?Am I right in thinking that the difficulty is sometimes raised for special events (e.g. the Lick Gengar) and so some of these may not be quad-able? via /r/TheSilphRoad http://bit.ly/2T75J7v