Alright, new here but I know that nobody will ever see this and most likely these ideas will never leave this one, lonely thread. However, I do have two ideas that I believe would make fun/unique classes that differ from the ones we currently receive, (Button Smashing One to Two Hit Kills). One idea is a Lancer (Yes different from Dark Knight, read on) and an Alchemist (Yes like the one from the Crafting Town, it was inspired by the outfit from Perma NX Boxes.)
So first off, this Lancer. This idea was inspired directly from the TERA Online class. However, being Maplestory and 2D, I feel the idea can be broadened. First off, keep that amazing giant lance, much cooler than spears, and then have a gigantic shield, mhm, huge. Now there will be two modes for the class in which you can switch freely, first being Ground Mode and second being Mount Mode. In Ground Mode, you will be able to perform many combo attacks with alternating Lance/Shield attacks/bashes. Most of these skills will be like the new Striker's in which it pushes mobs back and continually does so. On Mount Mode however, you will be able to have a trusty steed (Can have armour on it, changes w/job advancement) which you can deal heavy damage out with your Lance as long as you have the right speed (Like Mount and Blade: Warband where if you have a Polearm and charge with horse, does significantly more damage. This class would be an actually good class for mobbing, not as good for bossing unless its post Unlimited Update in which you can tank bosses and ride your horse to take it away from the crowd, so other ranged team members can attack from a distance.
Second idea is an Alchemist. Just like the Alchemist NX Costume, it will have the hat, gloves, etc. However, it will have a new mechanic where you can gather up herbs or have permanent orbs (each job adv.) and mix them together in a UI for buffs, damage, poisons, etc. It will have an UI such as Luminous, however it will show two potions pouring into one final potion. Depending on the herb and skill level, you can mix certain potions for healing, high poisoning, mobbing, etc. Also, it will consist of Left Potion skills and Right Potion Skills. Potions will have limits if they are Unique (meaning you had to dig the herb up) and some will be base such as regular class potions handed out. Right Hand potions are your damage ones, usually stay constant but can have over powered moves with only 1-5 uses. Left Hand potions will be the classes buffs, poisons, heals, etc. I feel if this class would be implemented by a developed staff, it can actually go somewhere.
Anyway those are my stupid ideas. Surely nobody will find this thread and most likely nobody will actually take these ideas into account. Just stating that if GMS gets two exclusive new classes, being a Lancer and Alchemist, I can say I had something to do with that implementation.