Reddit mentions of Quiksilver Men's Lone Walker Waist Fanny Pack Accessory, light grey heather, 1SZ

By those very measurements the G85 occupies over double the volume, 100%+ increase... Funny you calculated the weight increase but not that. I realize it's nowhere near that because the grip and EVF hump protrusions don't extend across the entire body, and that this is subjective to an extent, but you're trying to minimize a very significant size difference to people who very often bought into a system because it can be smaller.

Practically for carrying the camera it can still make a very noticeable difference IMO, even when using larger lenses. I have a grip on my E-M5 II and I take it off the L plate often precisely so it fits better in a bag. The way it sits in my not-a-square PD Sling 10L it has the hump against one of the inclined sides and the grip side against the also slanted front side. A G85 even with the same lens (say a PL8-18 or 17/1.2) would absolutely not fit in the same spot in the same bag, a GX85 would fit easily since it's the same size but w/o hump.

For a larger body I would need to move the dividers, minimizing space elsewhere, and it's already a tight fit in the other compartments. My 17/1.2 (on it's side) slots in into the exact space in the bottom of the opposite side of the bag (so I can stack atop it) and the GX850 fits into the exact space on the shelf created in the top/middle. (see pic later on)

Shoot I squeeze my E-M5 II with a smaller prime into something like this often, the G85 wouldn't fit in there even without a lens (GX85 would). Maybe you're accustomed to using larger and boxier bags, and that's fine whether it's out of force of habit or comfort, but it doesn't change the fact that smaller M4/3 bodies can go places larger ones can't. (coat pockets, different bags, etc.) I have a GX850 too btw and I use it all the time as a second body precisely because it's that small, it fits next to the E-M5 II° in the same space in my Sling.

The GX85 has many many advantages over the GX850 tho (not the least of which is IBIS & the EVF, or much longer video recording limits), and it's currently several hundreds cheaper than the G85 (cheaper than the G7 at B&H even btw). I don't quite understand what your issue with it is. The E-PL8 is pricier and has a really old/poor IBIS implementation, that's probably the worst value of everything mentioned IMO. The OP didn't even ask about the G85 or less capable bodies...

Waiting is his prerogative, and it's always good to know what's coming, but if it's really something (anything) remotely close to FF then it's likely to have little to no impact on the <$600 options he's weighing up. I'm in no way minimizing the value of the G line either btw, I think both the G7 & G85 were some of Pana's most aggressively priced bodies, the GX9 is a disappointment compared to those or the GX85.

°Just shot that for context, it's not packed precisely as I typically carry it since I just got back from a trip and had re-arranged it just for the plane ride. The headphones and some other stuff on the left side would normally not be there, I'd typically have a large lens on the bottom on that side (like a 17/1.2) and a smaller one + a pancake or Raynox atop it on the shelf made by the dividers. There's another lens & another pancake under the GX850, and slim chance a larger body would fit where the E-M5 II is on the right (PL8-18 on it btw).