I'm pretty sure it's already been suggested and if I missed out on it, my bad. It just seems easier to see a percentage rather then Very Low, Low, Fair, ect. It makes it easier at least in my opinion to coordinate tasks since I know that more variety in all areas of the tasks give a higher chance of success, it's just harder when we're kind of estimating how many people are on a task. It's also easier when we can just see how many people are already on a task to begin with. That way we know that enough is enough and it's time to move on to a different task.

you can click 'show Progress' under each task to see how many have already joined.

I believe he means on the main description of the mission, where it shows your success chance, not how far you are through each task within that mission. +1 to this.

The weight of each task against the overall chance is supposed to be hidden.