3) Small arm do not have projectiles because it would really mess up the engine to calculate the thousand of round fired in 4vs4 game. They can damage world objects PTRS destroying cover is prime example but that was done by the engine without a projectile being involved.
Err, I call completely wrong on that one. Can you provide a reference on that or relevant experience? They are still most likely being done with casting rays, or the CoH1 target cell-based approach, or other solution from the essence engine sometime between 2006 and coh2 release. Projectiles or not, it is still a standard O(n²) complexity
(as for as good any collision detection and response in older game engines) for the same in-game results, so what you say there is completely void of sense and logic.