We have heavy mist already (prior to the Mistlands update) and there is no way to clear it away, but the things 'in it' were not so deadly. I am sure some new balance will be achieved, but the mist is part of what makes the area so challenging; each step could uncover some new thing that will eat you standing face-to-face with you.

As an aside I am always amused by posters who write things like "Half their player base left..." over some change. Really? half you say? And you know this how?