From the 1CGS/IL2 GB developer's podcast (which was only in Russian), there came a few interesting points according to Flying_Anchor, and as noted by Stormbirds:
80-100 AI planes in a scene;
DirectX 12, PBR textures;
the visuals are better than in DCS;
increasing of minimum systems requirements (6 VRAM at least);
new AI logic;
better damage model;
more radio chats;
communications with ground radars (bearings, home vector, etc);
they will support GB, specifically Odessa and Karelia theatres;
they'd like to push Pacific theme despite Jason makes his own product.
Apparently the project, which includes a new game engine, is about 30% complete. If they are planning PTO, I think more competition makes a better product for players.