Did you check the gps signals with the "AndroiTS GPS" app? If it's all fine, kill all other apps when running Waze to see if the instability is memory related.
Location is ok If you're outside (for me). But I want to get location when I'm inside any building. I used to have Mi-3 and Mi-4 and location was working OK. Now with Mi-2S, you can't get location in a building.
You can get location even inside but probably not with GPS!
On XDA check Nogapps page, there's also network location thread with download. Location works even with wifi and 3g OFF. It uses cellular network, in other words anywhere where you can receive calls, there is a signal for you.
Yes, you're right! I just paste Networklocation.apk to /system/app, changed permission, rebooted and works like a charm.
I was making the same thing in the past, but back then - there was no multilanguage rom!