-BOSS
#More accounts you have - more brown box you will obtain, is faster to finish quest on 15 accs than collect 40 silver coins.
Doesnt matter how long and hard you grind player with more accs will obtain more box in way shorter time, later they just trade the item which they want box.
-PVE
#Ppl using multiple acc's to finish TMQ/CC/UD and play alone, almost impossible to find party for something, new players can't even finish ud1 or tmq1 you can see every day players that asking for help in korin, i can't wait for kraken/bacterian/cell where you will be able to keep whole drop only for youself.
#DW/SK can steal your spot any time because DROP/EXP will belong to player that make more aggro.
-PVP
#Ppl using multi accounts in budokai qualifications for easy kills or using them for kill u. sometimes u can see characters that not even moving its because that this alt didnt get in the same qualifications as the owner.
#Ultima/sk can kill SWORD/Fighter just by reflect and debuffs.
#tons of chinese multi accounts around arena that attack u
-Unlimited connections per IP
#allowing players to abuse everything that should be not allowed in MMORPG.
#We can't have daily rewards, daily quests, nice events.
#Fake guilds with million online players but when here is dojo war here is 3vs3 guilds because none of them can have 30 real members online.
i probably forget about some.