Metal Reaper Online is an MMO with isometric shooter and RPG elements, i don't see much shooter mmos especially in 2d~2.5d you can advance into predator that uses the machine guns and some gas bombs, they are the mario of metal reaper Panzer - tanky class that uses chain saw or flamethrower (chain saw gives defense and flamethrower gives more critical damage) sniper - they can cloak and use many traps supporter - a medic basically with mines and shotgun. http://mr.jcplanet.com/
have you tried ragnarok, trickster?
Ragnarok is a well known game for mvping and woe (monster vs player, highest dps gets a special drop and the rest drops on the floor) (war of emperium, a weekly guild competition where you infiltrate the castle and take out the crystal to capture the castle its not that hard to defend it!)
trickster is similar to ragnarok but it doesn't have any weekly castlesiege, it does have some boss killing and party quests though, unlike ragnarok which has human characters you start off with four different archtypes power - melee: Bunny (1v1) Buffalo (1vAll) / magic - caster: Sheep (choose 2 out of the 5 elementsfire,water,electricity,ground,air) Dragon (light or dark) charm - defensive/evasive: Cat (transforms into a beast) Raccoon (tosses cards) sense - Luck: Lion (uses gun but gun damage only scales of ac (accuracy 1 point of accuracy is 20 damage) Fox (is like a ninja, throws kunais or other sharp objects, they also toss mines.) it has many quests to complete and unlike most of games you can drill on the ground for quest items / exp.
www.playragnarok.com www.playtrickster.com
these are some diablo style graphic mmorpgs red stone, dark eden, mu online
http://muonline.webzen.com/ http://www.gamengame.com/games/online-game-media.asp?online-game-no=110 www.dklegend.com/
im currently looking forward to albion, das tal, shards online, lineage eternal, lost ark, tree of savior