And it also becomes a lot more obvious why the series went downhill in the third season. Roddenberry and Coon had such a huge role in fixing and rewriting the scripts-- much of which went uncredited-- that once they left there just wasn't anybody around anymore to keep up the high quality.
Not to mention D.C. Fontana, who became the script consultant late in the first season and continued in that role during the second season. To a lesser extent, John D.F. Black (early season one) and Steven Carabatsos (mid-season one) were also important to maintaining the consistency of the writing.
Has anyone else read the chapter on 'The Alternative Factor?' The author's conclusions there are rather damning towards NBC (and, to a lesser extent, the production staff), but his support for them is pretty lacking.
Basically, Cushman alleges that NBC forced a late re-write to the script eliminating the romance between Lt. Charlene Masters and Lazarus when Janet MacLachlan (an African-American actress) was cast in the role. This is plausible, I suppose, but there's hardly a smoking gun (or phaser) from which Cushman can make his case. He doesn't have an interview source making the claim, and the production documentation is far from conclusive.