1. I partially agree, at least the textures are of higher quality.
2. Nonsense, this is the only and main weapon of the guard, and in his left hand he has an unrealized impulse shield (the name of the textures shows this) + at the end of 2001, when the guard was made, the strider most likely did not have an attack from a cannon.
3. He is a mini boss in himself. You can only kill him with physical objects, and if you don't have them, you just have to run. He has melee attacks, even two different animations, and the kick animation is just an additional option.