Characters need motivation. And not only do they need motivation, they need plausible motivation.
For example, you can't just say "He wanted to kill her." Sure, it's motivation, but why does he want to kill her? Did she destroy his career? Steal his wife? Embarrass him in public?
So on this note, in planning my latest project via Excel, I've added a new tab. Sure, in each of my character worksheets, I have motivation for each character. But I realized I need to see all the motivations together. And in doing so, I could more easily see how each character's motivation worked for or against the others.
So think about your WIP. Think about your characters. Do they all have a valid, substantial reason for being? If not, can you think of one? No? Do you need the character after all?