Well, i think aida is a map with a lot of potential, and karutan 2 as well in my opinion.
How to make them more special, potential ideas:
1) change the spawn area of some mobs from other more "densely populated" / more oftenly hunted maps to Aida, or simply add something there.
Ex: Fire Flame Ghost spawns in beginner maps but is not for beginners at all, its for medium to high players. But, it spawns in the same maps with most other beginner level event mobs. Separating them would make Aida more popular (for card decks) and the beginner maps would be less searched 24/7 by hunters for card decks (that is a thing) and leave some gold rabbits or golden budge dragons for the others? This needs some more thinking. - or simply adding another event mob to this map - this needs to be thought trough so it doesnt tilt the crrent economy balance of the game.
2) Better "spots" . The #1 reason some maps aren't used / visited is because simply put, there are no good places where to level up there. Aida has like 1 or 2 and they aren't that great either. So maybe you can improve some of the spots there?
This is also true for karutan, where i have searched the whole map 3 times to find any decent spot, and the most i saw was of 5 (weak) mobs, and precisly 0 players.
This also has room for some additions..first of all..a couple of spots i think would be the right begining...and maybe ruud snakes? or some other type of mob that would rarely appear? Maybe move some from the dungeon, like the bali and soldier to aida, or some snakes in aida, make it thematic.. Case in point...most goodyes can only be harvested by 50+ rr players, turning lower rr players away from what i saw, maybe this is just a small demografic of the real numbers, but i think this is a step in the right direction to making the server more enjoyable little by little.
Edit: Zaikan for example can spawn in Kanturu / Karutan, both maps need some attention
Edit 2 : i gave it more thought, and kanturu (1-2-3) has nothing special except for being a good leveling up map. You can add Golden Satyors x 5 or 10 to drop Elixirs for Errtel crafting, spawn rates at 1 hour once with the Golden invasion maybe?
Edit 3 : Aida can have small ruud snakes while vulcan has the big ones only...Vulcan is 99% visited by high rr players and REQUIRES lvl 400, making it so aida has some...would balance the hunting...high lv playes wont "waste" their time hunting 100-400 ruud snakes in aida when they can do it in vulcanus...and weaker players have an opportunity to hunt ruud as well.