I believe the Spazer should be nerfed. I did a small test where I fought Torizo twice with end-of-prehardmode equipment (all pre-WoF); once with a flat-shoulder Varia suit and an Unreal Power Beam, containing a Charge, Ice, Wave, and Spazer, and once with Molten and a Legendary Night's Edge. This fight was conducted in Expert Mode with no accessories. In the latter fight, it took me a minute to actually do Torizo in, but in the fight with the Power Beam, I absolutely melted the thing in under 10 seconds. The Power Beam, I feel, completely outclasses the Missile Launcher at this particular stage in the game, as well as every other weapon.
Another thing I'd like to mention is that the Chozo Ghost's dialogue that mentions the Witch Doctor has a grammatical error in the last sentence.