Friday (July 6, 2018) was the last day of the Fourth Doctor block on Twitch, thus bringing a close all over again to his era. Those stories broadcast from August 30, 1980 until March 21, 1981 were to be the final episodes of Tom Baker's historic seven season run, and as such are historically interesting, due to the influx of the "new" that had swept across the program on that eighteenth season. There was a new title sequence, replacing the classic time tunnel sequence that had been a staple since Jon Pertwee's final year all the way back in Season 11; a new variation of the theme tune, with Peter Howell replacing Delia Derbyshire's arrangement (although the famous arrangement used during Tom Baker's run had been running since mid-1966); a new producer, with John Nathan-Turner replacing Graham Williams, and as such having a firmer hand on what had by that point become a program that ran amok both in terms of production and its leading man; new script editors, new stories, new companions, it was all brand new and felt little like what came before, with the possible exception of Romana, continued to be played by Lalla Ward until Warrior's Gate when she departed the show, and K9, with John Leeson returning to the part after an absence who also departed in Warrior's Gate, as well as Executive Producer Barry Letts, who'd steered the beginning of Doctor Who's golden age in the Pertwee era and was brought back just for this lone season to help ease the load on the untested JNT.
But the most obvious main exception that certainly tied Season 18 down to the past WAS its leading man, who was the last bastion of the old days except for his costume. Tom Baker has said that perhaps he had stayed a little bit too long in the role. After all, the only other actor who'd been in the part just as long was his predecessor Pertwee. Both Hartnell and Troughton left after roughly three years and three seasons apiece (Hartnell technically did shoot the first couple stories that opened Season 4 before leaving, so he was there by technicality four seasons) and with not many re-broadcasts of past Doctors on television, particularly here in America, it was Baker's Fourth Doctor that was for all intents and purposes, the first Doctor that many came to know and not many others. But who could blame Baker for wanting to remain there, season after season, year after year? To be the anchor of a much beloved science-fiction program and the hero to millions and millions of children, especially after having endured a lonely, gloomy childhood as Baker did and suffering near success and much failure before Barry Letts and Terrance Dicks obliged and signed him on.
But it also has to be said that Tom Baker was not the easiest to get along with. It seems like sometime after Season 13, or perhaps during production on Season 14, things became a little strained between Baker and most of his co-stars. His infamous feud with Louise Jameson, who played Leela during Season 14 and 15, and his increasing ego in regards to having say over actors, writers, and directors had become out of control. Graham Williams, who'd replaced Hinchcliffe, didn't have the kind of temperament or creativity to find ways to accommodate Baker. That isn't to say he didn't try, as the Season 16 story arc for the Key to Time quest is an entertaining, if flawed, execution of the grand ideas Williams had, but also served as a preview of the incoming silliness that would surge through into Season 17, where it reached its apex.
John Nathan-Turner was having none of that. If only because Baker had been signed on prior to JNT's ascendancy, he probably would not have had Baker in the eighteenth season. And it's also very likely that he didn't like how many concessions Williams gave to Baker (case in point, watch either The Horns of Nimon or the incomplete Shada, and then fire up The Leisure Hive next, and you'll see a completely different vibe incongruent with one another) and really, above all else, didn't care much for Baker's Fourth Doctor. It could be that Baker wasn't used to being told "No" that likely hampered his performance in a lot of the stories, or it may have been the behind the scenes havoc in his relationship with co-star Lalla Ward, or even it may have been his own ill health, giving his performance a lackluster, almost deathly mood. It's one that many critics say give the stories a kind of theme, with entropy and death becoming a constant presence in the stories.
Had the stories themselves been up to par, this would've been an interesting direction to take the show, particularly for the Fourth Doctor who had delved into such darkness throughout the Hinchcliffe era of Seasons 12-14. As they are, the stories aren't bad, but very hamstrung by some pretty sub-part effects, and certainly not helped by Tom Baker's lethargy throughout. He seems to come alive especially in State of Decay, perhaps because it was from a script by Terrance Dicks and felt like the old days, and is on point in Keeper of Traken. But when getting to Logopolis, things start to feel, well...not right. For his finale, sure, the Fourth Doctor, the "Hero Doctor" goes out saving the universe just as he did time and time again.