The McCoy seasons were uneven; I hated both "Silver Nemesis" and "The Greatest Show in the Galaxy," though I like some of the much-hated ones like "The Happiness Patrol" and "Paradise Towers." (And I kind of like "Ghost Light" too.) But they did have some of the series' most brilliant serials, particularly "Remembrance" and "Battlefield." And even the less successful ones were interestingly experimental. In a lot of ways, that last couple of seasons presaged the modern series, in that it gave us just about the most richly nuanced and complex companion the series had ever had up to that point, and made the Doctor a more complex and ambiguous figure as well. There was definitely a new maturity to the series in those last few years, which I assume came from Cartmel as story editor and from the writers he brought in.