The f/2.8 and f/4 lenses make sense.There is another lens with similar focal range grouped with the other new/upcoming compact F4 lenses, so likely it will be F4 too.
Someone wondered why have both a 50-200mm and a 50-230mm upcoming, and I think F2.8 vs F4 must be the reason.
It is interesting so many upcoming Pro lenses, mostly telephoto, but only one non-Pro, which is super-telephoto. Maybe Olympus trying hard to distance the system from smartphones. Telephoto might be an advantage of Micro Four Thirds over full frame too.
Tele IS an advantage of m4/3 over FF.
At the same magnification / angle of view, I can use a shorter m4/3 lens than a FF lens.
For me, one of the m4/3 advantage is simply from the logistics of carrying the weight and bulk of a BIG FF lens.
The Panasonic 35-100/2.8 is half the weight of the Nikon 70-200/4, and about a quarter of the weight of the 70-200/2.8.
The Olympus 40-150R is smaller than my film 135/3.5, and way smaller and lighter than my film/FF 75-300.
Both are non-pro lenses, so the comparison is valid.
There isn't a pro FF 70-300 to compare the Olympus 40-150/2.8 to.
The Olympus 75-300 is so much smaller and lighter than the Sigma 150-600.
While weight may not be an issue if you are in your 20s or 30s.
When you get older, every extra pound of gear is harder to haul and shoot with.
I have past that point. To keep shooting like I have, I had to reduce the weight of my kit.