If we use a reasonable definition of hard, like what percentage of the population can learn a task/skill/subject. We could say the smaller percentage of people that can do a task/skill/subject the harder it is.

And the larger the percentage of the population can learn the task/skill/subject the softer it is.

With this definition we can still use the words hard and soft and I don’t think it changes too much how we use them now.

And then any social consequences that come from the use of the words would just be inherent based on a reasonable definition.