Why are the effects global and not adjustable per person?

Because Livemix was designed to be volunteer friendly and easy to use, setting up effects for each channel can be done globally from one personal mixer. Setting up EQ and compression on 24 channels for every person on stage would be a nightmare (with the MIX-32 that would be 768 channels). With global effects, each channel can be optimized to fit in a mix perfectly so that each performer just needs to adjust volume and pan.