I'm loving this feature. I wouldn't even call that movement chopping, it certainly isn't violent for me like it is in your experience. Two gentle wrist swings is all it takes to activate.
It's super natural for me to use it now any time I need a flashlight. I don't even think about it, I just reach into my pocket and by the time I direct the phone where I need, the light is already on. Extremely convenient for me.
Sorry to hear yours doesn't work well. Have you tried checking if your phone's accelerometer is working properly?
I picked a cheap phone on purpose, but I don't know how I'll be able to go back to a phone that doesn't have the chop to activate the flashlight gesture. It works everytime for me, and it's a pretty easy gesture. I've never had it go off accidentally either. Same goes for the double twist for the camera.
The guestures have been such a pleasant surprise for my budget tier device.
I had to use a Huawei for some time, and I never realized how much I rely on the gestures. And how much I hate bloated custom ROMs. You can say about moto as a company whatever you want, their cameras are trash, but the custom ROM is, apart from it containing gapps, perfect.
Loved it on my Moto X 2014, not sure how you're doing it wrong. double chop, small movement, around 30 degrees. Hold the phone flat against your palm, like you're shaking hands with it.
Works a little too well sometimes and it turned on when I was running with my phone in my pocket.