I'm currently working on a game, but i want to know if the concept is even feasible in AGS. Basically, The game would be a large open world where Enemies and bosses move around in real time. In other words, The player could stumble across them any time, and they could interact with each other too despite being in different rooms than the player. Can AGS handle this? Would making GIANT rooms as sections of the world map be a more logical thing to do? Thanks!
Every character scripting event is handled in the global script, which allows code to run every frame, so I don't see why not. NPCs can also move between rooms without affecting the player experience in any way, so there isn't any need to make uber rooms. You can say that AGS was designed to allow this kind of game.
You'll have to limit the characters' blocking functions to only run when intended. The real challenge will be keeping your code in the global script optimized, because I assume you'll include some form of AI. Character objects can be extended with new functions without any hassle.
This is pretty much what Heroine's Quest did. Scripting this is a challenge though, not something you can crank out in a few afternoons, especially not as a beginner.
I wouldn't use overly large rooms; the first iteration of Dustbowl used a single large room for the map and it made AGS crash occasionally.
Either use multiple big rooms (similarly to the Overworld in Zelda for SNES), or use a screen sized room and a tile engine (like Zelda for SNES).