Remember Birds of Prey has to run on what is effectively a PC with 256mb RAM and a 256mb Graphics card. From the sounds of Storm of War I would say the absolute minimum specs needed would be around 2GB RAM and a 512mb Graphics card, if not more. Then bear in mind that the visuals from Storm of War and Birds of Prey aren't hugely different, at least at first look, and I think you will understand why Birds of Prey can't compete with Storm of War on damage modelling.
Incidentally, this is Storm of War's damage modelling. The large holes are caused by Flak, these are preset but there are presets for hundreds more impacts. Effectively, wherever the plane is hit a hole will appear. The smaller holes are bullet and cannon shell impacts, and these aren't preset, the holes will appear exactly where the bullet hit.
