I think season seven's poor quality is more easily attributed to the rise of the mediocre Micheal Piller, Rick Berman and Brannon Braga than the death of Roddenberry. TNG had some good writers and they had some bad ones. Also, if I remember the commentary I listened to years ago correctly a lot of the good stuff from TNG was done despite Roddenberry interference not because of it. One only needs to look at the ham that is ST:OS and the first 3 seasons of TNG for that, because season 1 to 3 were basically rehashed Star Trek Phase II scripts that were more pure Roddenberry. I'm not trying to diminish Roddenberry's importance as creator but to attribute all the best to him is disingenuous. After TNG ended the good and the bad writers seemed to split up pretty evenly. Ira Stephen Behr, Ronald Moore, Rene Echevarria and others(I'm sure) went on to create some of the best of star trek in season 3-6 of Deep Space Nine. While Piller, Berman, Braga and others went on to make Voyager, Enterprise and then the franchise killer that was Nemesis. Bad shows all around, and their horribleness can be attributed to the writers because the casts were mostly ok.