So the OP has only made 1 post in this thread?
I see Horrendous flying skills and the lack of any video editing skills, none!
(I can not believe no one here has even mentioned it)
First off, you need a serious amount of flying practice, you are just terrible and even the best gimbal on the planet won't save you or make your vids look any better.
Your jerk, jerk, jerk, jerk, jerk, jerk jerk, yawing the craft back and force is a sure way to set the x3 up for failure, (turn the "yaw" expo down to 30%).
You never came back and answered any of the important questions The Editor asked you, (camera settings, nd filter).
I don't know where you disappeared to, but I hope you are out flying right now, because smoothing out your flying will be 90% of your battle.
Go find an unoccupied park in an open area and practice flying around a slide, or a swing set. Practice flying diagonal and sideways. When at home in your yard, launch the I1 and stay about 2 feet off the ground. Fly all over walking behind it, use it as a leaf blower, follow the sidewalks, fly it pointing away from you as well as it it pointing directly at you.
You need to practice flying before you can expect to get smooth videos ..... period.
Lastly, editing ........ Please don't post a 9 minute video of your problem.
There is no way anyone is even going to bother watching the whole thing (unless they are extremely bored or died at their desk), anything towards the end that may be important will not be seen by most. At least learn how to use windows movie maker (if you have a pc). There are a million "How To's" on you tube and in just a few minutes you will learn how to cut up your videos and only post what's needed.
ps - learning important things
like what is expo and how to use it is imperative.
pss -
reading the manual would help You a ton.
pss dji makes peeps believe they can simply take the I1 out of the box, charge the battery, then make videos like Remote Rider's, (it
doesn't work like that).