1) This lightsaber appears to allow blaster fire to pass through undeflected.
2) There is no discussion of how sabers parry each other instead of breaking.
3) It appears to have a "blunt" tip.
1 and 2 could possibly be explained as a Force-related effect. Vader has been seen to deflect blaster bolts with his bare palms, so we know that the Force is capable of doing this; perhaps something in the design of the lightsaber makes it much easier to perform this feat with the surface of the blade, or perhaps it even produces a field or resonance in the Force that deflects energies without conscious effort beyond that needed to power the saber. Vader's deflection power may be inspired by study of the saber itself.
This implies that a sufficiently powerful Force user could parry a lightsaber with their bare hands! However, given that the blaster-deflection trick appears to be quite difficult, saber-deflection may be possible in theory but beyond any Jedi's abilities in practice.
2 could also be explained by advanced materials technology. The filaments, perhaps created by Force-guided elemental deposition, may simply be too strong for human muscles to break by whacking them together.
3 could perhaps be solved by making the filaments loop back around at the tip instead of terminating in a ceramic cap. A single filament, then, would spiral clockwise out from the base of the blade, make a 180-degree turn, and spiral back inwards counterclockwise. The only problem is that this would produce much greater light pressure in the tip than along the rest of the filament; saber designers would have to take this into account to avoid catastrophic failure.