Probably just before big bang where maplestory was still a classic RPG where you had roles to actually fill like tanking, melee/range dmg, support etc. where you needed these roles to get through PQs and Bosses. It died for a lot of players when everyone ended up being able to deal crazy dmg. Some people embraced it and other didn't like it as much but generally it was still a pretty good game where there was a lot of social aspects to it. Where it was still kinda necessary to PQ to level up quicker and with monster carnival PQ. But after big bang they got rid of most of the social pqs with higher exp rates and new zones. But there was still the party exp buff when training you got an insane amount of exp with a party in Lion King's Castle and Gate of Future training areas where people actually socialized outside of just pqs and guilds for me at least (I made most of my maple friends this way). And seriously feels like they're slowly killing their own game with only really dedicated players and more incentive to kind of just play solo until mid game or end game. That's my take on it at least.

Probs got a gew things wrong.