I dont know where you're getting these assumptions from, because they are not correct.
A player is not a single point object, they are treated as a 6 sided (box shaped) object, this is why if you hit somebody from above it'll play "blowbackdown" animation, when you hit their left side it'll play "blowbackright", what ren is describing is the way that you can only score a hit from the front plane of the hitbox, an angle hit, is a hit that avoids the front plane of the enemy and hits the left or right plane of their hitbox instead. They are not counted as limb shaped hitboxes for a reason, because back in development, that made it near impossible at the speeds involved in ESF to ever hit your enemy when model hitboxes were used, model hitboxes are created by compiling a model. You also say how the engine does not calculate the velocity of a hit, while this may be true in 1.2, it is not true in 1.3, the speed you are travelling when you connect with your enemy has a direct relationship to the distance/speed of the knockback. This has nothing to do with the physics engine itself, but the code that determines what a simple melee hit does, and how the momentum of a character will effect the next, in 1.2/1.1 it was just a value used for the distance and speed of knockback, now, like I say, it takes into account the speed you were traveling before hand.
Besides, it's already been mentioned that Bullet physics engine is currently being implemented.