The premise of the Olympus 12-100/4 seems interesting. I tried it out in a store and sort of liked it.
I already have the Panasonic 12-35/2.8 and 35-100/2.8, though. And the 12-100/4 (561g) weighs not much less than both Panasonic 2.8 zooms put together (305g + 357g = 662g). Having all the weight in my hands feels worse than having half of it in my bag. Not to mention, it's a stop slower. That's a lot of trade-offs. It would be redundant for me to own all three, so it would have to be a replacement for me, and I'm not sure I want to make that exchange.
I could see myself renting it for hiking, or other rare scenarios where I really don't want to change lenses.
Or, I suppose, if someone puts one up for sale at a sufficient discount, I could see myself impulse buying first and asking questions later.