There is no doubt that a good emcee will make use of positive body language and body movements to establish a rapport with the audience. However, this does not mean the individual will completely ignore the nature of the event. A corporate event involving the top management is not a place to jump up and down like a comedian.
A good emcee will have the ability to establish a connection with the audience without resorting to extravagant gestures. This is not to say that all extravagant gestures must be avoided. However, it must be used with proper understanding of the nature of the event and the quality of the audience.
It is easy for an amateur to memorize instructions about positive body language. However, only a good emcee will know when to use the instructions properly. This is the reason why you should go in for a qualified professional. A good emcee will possess not just theoretical knowledge but practical understanding as well.