I use a crown to play Tekken with. Comparing a Korean stick to an American stick comes up a lot but it's a much different kind of thing. You're getting a much stiffer and more "open" feeling than a JP stick for sure, but the dimensions/switches/materials used make actual actuation a lot smoother than something like an American stick.
Switching to a Korean stick in Tekken didn't magically solve my execution problems or make dashing easier really. The types of motions it actually makes a difference in are the ones where you need to return to neutral hitting 1-2 directions along the way, then quickly go to a new direction. Examples being like wavedashing and KR backdash. Those types of motions don't really exist in 2D games. If you have been using JP sticks for years and need something to go to neutral faster, Seimitsu will probably have better options for you.
If you already have a few JP sticks around that you like and are going out of your way to get an eTokki, I would say to grab the KR version just to try it and have something different. It might give you what you're after and it's nice to have in general. I think it's a waste to order a stick from Korea that has the option of having a KR mount and not taking that option(they are basically the only ones to offer it).
If you're worried about it being the big stiff monster like an American stick, I wouldn't. I've used 2 different Crowns now and briefly messed with a Fanta. They have some similarities with American sticks, but make them feel like cheap knock off toys in comparison. That's just my opinion though. I hate American sticks and have used mostly JP ones, but I also use a KR stick and love it just as much as my JP ones.
If you feel comfortable with opening up your stick, order a crown stick from focus attack or paradise arcade and put it in. Just make sure the stick is JLF compatible.
The etokki onmi is $250+ after shipping. It's a great stick and I own one but it's expensive as fuck.
Also this. You can just try one of the KR sticks that is compatible with a JP mount.