OK, if for some crazy reason they do a DK3 remix I have some ideas.
1) Since there is a secret Donkey Kong Junior sprite in the game, maybe give Junior his own board. Like the gold board for instance with his own special bugs. Maybe a bird or a flying snapper from from DKJr?
2) The bonus stage. You could make it where Stanley gets bonus points for hitting worms that climb down the trees. Or you could just do a Galaga like thing, and have Stanley shoot the bugs flying in formation.
3) Maybe have a super super spray. This is basically activated when someone dies without using their super spray. Now they have the super super spray. So what does the super super spray do? It knocks out Donkey Kong in one hit. Basically use the scene where Donkey Kong falls to the ground on the gold board. Of course you can only use the super super spray for one board, and it goes back to a normal super spray the board after.
4) Have an all queen bee board. The entire board is only queen bees. Instead of there being 4 or 8 for a level there are 16 or maybe even up to 24, and they come out two or three at a time.
5) Have an all super bug board. When a bug steals a flower it becomes a super bug. Maybe have a board with nothing but super bugs. have them come out three at a time. Of course super bugs are hard to dodge with more than two of them on the screen so maybe the idea will be scrapped for difficulty.
6) Create another set of ropes, and have Donkey Kong Junior also come down. So this time you have two sets of apes to worry about.
7) Create a killscreen like there is for DK, and DKJr.
OK, most of these ideas are not practical when dealing with the original code, but hey it's an idea. Will there ever be a DK3 Remix. Who knows, maybe one day.