In any show with a long history of coming and going, THE TIME WARRIOR falls into that "moment" in the life of the series where everything is changing.
This is the beginning of the end for Jon Pertwee as the DOCTOR, it's the introduction of Elisabeth Sladen as one of the most popular companions in the series history, SARAH JANE SMITH, it's the first appereance of a SONTAREN who, like Sarah Jane, would continue on through the series up until the present day. We hear GALLIFREY for the first time. It's the last days of UNIT, the return to time travel as the norm for the series and the return, as well, of the historical story (which would turn up a few times more down the line with Tom Baker and Peter Davidson). THE TIME WARRIOR has so much going on it's a wonder that it manages to hold itself together so well... but it does.
The story is simple... a snoopy, plucky, "girl in the moment" reporter slueths her way into a mystery and then into danger, as the Doctor takes the TARDIS to the Middle Ages to rescue some time-napped scientists and save the world from both a seasoned Sontaren warrior and a pack of bloodthirsty pusedo-frat boys who have it in them to go out and storm castles for supplies.
There's danger around every corner and while the threat is real (and at times disturbing - using the Doctor as target practice, with real guns, is a calculated risk, not simply because of the violence, but because the threat level here is grounded very heavily in reality and unlike ray guns, the chance that the Doctor will be shot, bleed and die is something you can see happening all too easily. While guns in the UK are rare, the fact that they appear here as they do really is a shock - it's a very American style of danger that you didn't expect to find in DOCTOR WHO at the time), you can't help but smile at it all as both Sarah and the rest of the cast give it their level best in making all the rushing back and forth between plot points work.
Linx is a dymanic villian, he's aloof, yet interested in everything around him. While he is in a rush to get back to his war in space, he's still got it in him to tinker with Earth's history and accelerate the arms race looking for possible allies or fodder down the line. Despite being a champion for war and destruction, Linx is a reasoning alien that matches the Doctor's battle for peace. If there is any real downside it's found in the fact that Sarah settles in a bit too easily into the routine and Pertwee's performance, while never bad, never rises above professional - he is the Doctor, but Pertwee, the actor, is just filling the suit from now on until his final story.
The disc comes complete the standard extras... commentary with Sladen, Letts and Dicks is casual and the series is recalled fondly. There are a number of details that stick out, but there are some frustrating moments as Letts will spend a lot of time on some minor details (which, while interesting) that drag out the commentary at all the wrong moments. Sarah's first introduction is marked in a whisper by Sladen instead of a roar, because she doesn't want to interrupt Lett's story about the director which ends up in a dead end.
Likewise with her first time in the TARDIS, Lett's is missing the moment in history while detailing production backstory. It will frustrate you, but, overall the commentary is good. TEXT COMMENTARY is overstuffed with scene breakdowns and alternate story takes, but stick with it, just have the remote handy as some paragraphs appear and disappear quickly.
THE TIME WARRIOR at the time it was made was a solid, well played story that would turn out to be rich in history for the series down the line. For fans, it's a must, your collection could not be complete without it.