As for me:
Great Character Customization (Where everything is editable *with limits*)
Balanced PVP and level 100 cap with advance classes (max: 2 class levels *ex: beginner - trainee - professional*)
Awesome market and auction system (Auction used for gears and rare items that costs a lot, vending for food, pots, necessities.
anti-bot and anti-hack system (especially active GMs 24/7)
Balanced PvP (grand fantasia has a pretty balanced PVP, which pisses me off cuz I don't know what class to pick cuz I usually pick the OverPowered class :P)
SIEGE IS A MUST (RO = WoE, PW = TW, Castle sieges with rewards of course with world wide pvp, meaning its 1 guild vs everyone)
Real time PvPvE (Aion failed at this one for making a stupid PvE content) it means, its a wretched world. You can die anywhere if someone kills you. (people might hate this system, but I don't want to play with them. Carebears not allowed)
Plenty of Classes to pick balanced for PvP and PvE (role wise) - Summoners, Assassins, Rangers, Guns-men, swordsmen, cleric, sorcerer, blacksmith, merchant,
Sexy outfits ofcourse ( I xdress all the time)
decent grinding experience (meaning, the more you grind, the more powerful you get.
decent quest with good rewards
good manufacturing skills (I actually loved Aion's Manufacturing system, except its really weird that I have to go back to the town just to build something.)
no player limit event - once a month, all servers vs all servers (1 server active for 2 regions (1 for na and one for eu) World Clash, Lag Clash~ a great event PvPvE wise meaning, All vs All with special mobs included.
I'm tired, so I'm stopping here
good community !! <---!!!!
everything doesn't come down to the money you spent on the game -_-
npcs seem more real
good music :)
I love watching cutscenes too
got a plot. not just endless hunting- quest quest - grind - quest - grind grind grind
no hackers or botters :'(
no afk hunting bot implented !! -_-"
good servers. no random downtimes and lots of lag.
choose between resolution + windowed or fullscreen mode
rewards for being long-time members :>
non-screwed up drop rates etc
lots of items and quests but not too many you don't know any names of whatevers
I'm tired too so stopping as well xD
Kyouya senpai~~~ <3
i am looking forward for a good war and good friends.
no godly items so everything is balanced.
i don't like complicated 3d graphics that's why i like ragnarok online.
no bots and active GMs
and no payment