MapleStory 2, welcome.

I can't tell since I haven't ever played WoW but I'm pretty sure WoW world is like L2 world and although a look at the map makes it look divided

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it's actually seamless with a couple dungeons where you can only enter via a NPC(although those areas are along side the rest of the world) so IMO it looks more like what Dystopiq draws as open world(huge world thats one large map with a few small dungeons that aren't directly connected to the rest of the world).

Yeah, the entire world is seamless, you only get loading screens when you go to a different continent, or you enter an instance (dungeons, raids, PvP). Raid instance entrances look like this though, a doorway not an npc.