Custom map, not overdetailed showoff crap but a clean RPG style, a big map with well placed spawns and well hidden quests
Vocations well balanced, decreased damage both magic and physical so it would be a bit more like 7.6-7.7 system.
Oldschool pvp system, by that I mean removal of Cipbot so the fighting requires skills and not only a decent lvl
Rune system completly changed, removal of stackable runes, sd's having more than 1 charge etc etc. so the games becomes more challenging for not only 12 year old children. Also all potions ought to be removed or changed.
Low rates such as exp rate 2-3x, m-lvl 1-2x, skills 2-3x, loot rate 1-1,5x
No training monks, training chambers or whatsoever which makes the game easy.
Limited Donations so for instance u can't buy yourself a 100 lvl character within a day. More like 1 donation an account and you can donate only once a month or every 20 lvl's and recieve for example in exchange for 5 euro donation 35k gold or 6 bp's or uh's or so. That would make donations usefull, but yet they wouldn't make the donators gamepla way easier for them.
Premium it should be free
IF a balanced donation system as above would be introduced
Quests completly custom, but a bit more challenging then simple go,kill,find a lever, open the doors, kill again, get reward. Maybe some Instance/Raid style quests? Long, exhausting and requiring a lot of knowledge about the lore of the world?
Cities - map should not be spammed with them, they ought to be well placed, not too big nor not too small so at least 30-50 liveable houses with 2-4 GH's a city. Also not a spammed one's, but RPG style with good history and lore behind them!
LORE! - Good OT should have superb lore behind it. A lot of books to read, a lot of possibilites to talkw ith NPC's and learn new stuff about the world with possibilities of actually unlocking some hidden long quests wth unique rewards received only one time on whole server!