That sounds like the high res mode that already exists, probably hand held like the E-M1 iii.
I see that menu button is still in the least accessibly place it could be, but two stops better ISO sounds good.
Slightly better IBIS as well and much improved EVF is a real plus, bigger body i'm not so keen on.
New battery giving they reckon 520 shots using the rear screen, so in economy mode should last all day
Can't quite work out if the BLH-1 battery is compatible or not, getting conflicting reports on that detail.
Definitely needs a new battery grip if you use one, that ain't going to be cheap
Still its under two grand, only slightly and nice to see new m4/3 cameras coming, GH6 soon as well.