Have you tried asking the folks at the General Gaming Discussion
There are very few 2D-pixel MMORPGs out there. (You can probably guess, especially the one with the Porings.) However, I remember another 2D pixel that a few ggFTWers tried (and stayed) is La Tale
. Never played it, but it's like.. Cuteer than Maple Story?
ggFTW has a huge enclyclopedia of MMORPG listings, so if my suggestion is not working, try it's "Find your Game
" system first before you can ask any veterans. ^^;
P.S. If you don't mind 3D models, I think Eden Eternal is closest to Trickster, but with multiple classes (and I mean ALL OF THEM) you can unlock for each character! You can also swap classes anytime as well. :O