I agree, writing is a skill. My point was that when it comes to documentation, other skills are primary.

So--I wouldn't advise developers/writers looking to improve documentation to 'become better writers', I'd advise them to focus first on the other other skills, because without them 'good writing' in documentation is worthless. Put another way, the ultimate measure of good documentation is: how well it helps the user accomplish their 'jobs to be done'.