I have said before on here and I'll maintain it, DJI's taking one of the smartest plays here. Especially on mid-high end productions, regardless of any other factors, it's going to stay primarily Arri. If you make a traditional camera and try to compete, you'll have a huge uphill fight.
On the other hand, if you make a camera that takes something that's a pain in the ass, whether it's Arri or another decent camera system, and your thing makes it really easy, your camera might get used in parts of films that are shot on Arri or Burano or similar. Putting cameras on a gimbal is legitimately annoying. Wanna have that gimbal-based camera track subjects? Time for hacks like putting a second camera on the gimbal and needing to use multiple tools to track and monitor. One of the Ronin 4D's real superpowers is integrated tracking based on what the camera is seeing.
Today, a friend and I shot some tests with mine while between blocks at a local film festival. In the first, I experimented with an "impossible" shot where I tracked her walking and then had her pause while I pulled the camera back, planning to do a faux dolly zoom by reframing in post. It's imperfect, but with some practice and a less ambitious distance, I think it could play.
For the second, I recently got a Hydra Alien and wanted to see how it would work. My car is a worst-case scenario for rollers - the Wrangler has an extremely stiff suspension. Yet, after 40 minutes of stumbling around with putting the Hydra on my car for the first time ever, I mounted up the camera and had my friend drive while I operated. There are some micro-vibrations, certainly, and I might experiment with the alternate/softer shock plate, but it's kind of amazing how turning on autofocus + tracking on a random car on the road resulted in such great footage.
The last shot was to see if I could do a Tarantino-style shot spinning around the subject. If doing this on set, I'd want to set up something to ensure a consistent distance to the subject(s), but similar to the others, given the results after doing no planning or setup, the results are a bit unbelievable for just getting to the parking lot and saying "Hey, I bet we could do this. Let's try!"