It would be cool to have better control over your jet-pack. The jet pack we have now can only really go straight up and down, yes you can go left, right, forward and back while in the air but its slow to build up that momentum. The only real way to get the jet pack to work is to run on the ground and then take off (like a plane) even then its still slow.
There can be both jet pack models the normal 2,000 unit one, and then the new one could cost between 5k-8k units. Now what makes this jet-pack different? This jet-pack is way better in the air. Instead of the thrusters only facing down it has them all over the pack. You can fly at faster speeds in any direction, want to go forward there is a jet on the back that pushes you forward, it can slow you down and take you backwards. left and right are a breeze to handle. No more of this weird slidey ice thing we have now. Its sharp and responsive.
While in the air you can engage hover mode, and it does as its sounds, you can just float there in the sky (you can still fly around) It also has the ability to ascend and descend at will. Instead of waiting for your dude to fall to the ground like a leaf, you can fly down a lot faster using the jet-pack.
While inside shops or condos, instead of smashing you head into the roof and then being flung about like a ice hockey puck, it stops you at the height of the door frame so you can fly out of the shop. The same with the train station, I hate getting caught up in the rafters, this new jet-pack would stop that from happening allowing you to fly out of the station with ease.
You can also customize your jet pack. I know someone has said about that custom trails already (great idea (TheHackingFox)) But you could also change the colour and even put stickers on them (either from the web or from a in game selection) you could also have streams or other form of tassel hanging off the the pack. Basically allowing a fully editable jet-pack so people can express themselves how they like.
TLDR: Sharper controls, ascend and descend, stops you from hitting your head on stuff and getting stuck, fully customization with colour, stickers, (TheHackingFox, Custom trails) and tassels of any kind, 5k-8k cost.
Sorry for the long ass read XD Hope you like it!