I would love to find that the limit in the reward store upped to 5 or so a month, or possess clean slates drop a great deal more often (perhaps from zak, hilla, etc) to get down them to 5-10m a piece.
Untradable equipment - largely Android hubs, but also sweetwater gear, etc.. As someone who makes most of my money off of hearts and sweetwater, I would rather be broke and find something else to market and be able to trade these around my Maplestory M Mesos account. As of this moment, these will be the very last thing I scroll/cube... assuming I ever get around to them! Even being able to sharing label these items would be much better than nothing.
I know GMS is limited to what it can do, but Spell Traces need to be upgraded to reflect what normal scrolls can perform. I don't mind weapons being trapped at 9, so that they can make money off Primes with Marvel, but Android hearts ought to likewise be in a position to have 9 attack! This would not hurt the Prime marketplace, as min/maxers would still need them. As someone who's probably considered mid class/mid game... These are the biggest glaring flaws to me.
I've played walnut for some time, but still do not understand the best way to produce billions of maplestory2 mesos. I have tried elite supervisors, but they're so annoying to find and to even get maplestory2 items. I need more damage in my end archer, my harm range is 78000-90000 (level 153}. Everything is so gosh darn expensive and I cant fund my characters values crap.