While I can't go into specifics for ~reasons, I'll just say that you should definitely get the Z2 Force instead of holding out if you don't like the....rumours. Then again the longer you wait, the cheaper it'll get.
I'm really looking forward to the next gen. 6" 18:9 = 5.5" 16:9, just taller, and it's amazing how much more phone could (hypothetically speaking of course) fit into a Moto Mod-compatible footprint. Especially when the front-facing scanner has mysteriously disappeared and the extra screen real estate essentially replaces the bottom bezel with the nav buttons/what appears to be a software version of one-button nav.