You do not need "the." For example, "I will have half of the pizza."

yes, depends on context are you the kind of person who feels that the glass is half full or half empty, or do you even know the half of it?

What I wrote is this:"However, many people are currently heaping criticism on it because they think that it replaced the half of the panel in an unreasonable way." I'm confused ㅠㅠ

(the) half of what? Could you give an example sentence so we can have a hint at what you have in mind, or how you think they should be used?