I found the 'Hallmarks of Cancer' papers by Weinberg and Vogelstein to be very well written. While those are reviews, their research articles are well written as well.
Given that attitude, your mileage may vary with these suggestions.
I utilize primary research all day every day for my job and my definition of good academic writing is clear, concise writing that enables me to answer the specific questions I am seeking to answers for quickly and in a manner that allows me to confidently cite the work (assuming the relevant information is present within the manuscript).