I have been thinking about this for a while... before getting started i would like to say that if a new update is developed, changes should be made to the game to make it match the new update. Like, before the 9.0 update, there was that black ninja jumping around when you start the first quest, now its bugged as i think, there is no more black ninja animations in the very first mission.
Okay... So i wanted to suggest to add a story line, which take you to a final boss and you gotta defeat it to complete the chapter.
It will use the normal bosses as there is now, and i would like to suggest also to add a new boss lol. Maybe a giant magmagon with a crown? (this game is for kids sooo, just trynna not change it.(the crown thing looks childish tbh xD))
It would be nice if you are able to...like... create a party/lobby, so that you can complete the missions with your friends and so. (i think it will cost robby so much so idk about it.)
Another thing, what about adding a level cap? like level 5000? (I don't really think some one will get to that level in the nearby future.)
P.S: please don't the missions like to buy/get things.... like make it to kill the monsters to reach a place and advance to the next mission? make it like you have to talk to an npc to start a mission, not just start instantly when you finish a mission.
(and maybe make it that you can invite friends to the missions to help you, idk, most good games got that feature.)
Thats all i got for now, i may get any ideas later.