"The Sensorites" is not very good. In fact - whisper it quietly - it is probably worse than "The Keys of Marinus". At least, that had a portmanteau format and, if you didn't like one setting there, there would be another along in a minute. Here we get six episodes in which almost nothing seems to happen, certainly nothing of any real interest. The Sensorites themselves, leaving those pesky feet, do actually look surprisingly good, in spite of the zips, although the idea that are all identical is clearly absurd, They must be the most timorous race in the universe. This is not a promising premise. They are afraid of everything it seems (bright lights, loud noises, making decisions) even if they do possess some pretty advanced technology (see later) and apparently don't need vacuum suits (perhaps there is a pressurised walkway around the spaceship). If this were a story of the Sensorites overcoming their timorousness with the Doctor's help, there might be something to get our teeth into, but the humans are as bad as the Sensorites. Lorne Cossette did not so much phone in his performance as radio it in by Morse from the Southern Ocean, but at least Stephen Dartnell is trying. A bit too hard. It's not until we get to meet the Commander that things liven up. We can see what the story should have been about and this fits with the theme of Newman's Yesterday's Enemy. A problem was commissioning a writer who clearly had little feel for sf. For all his many flaws, Terry Nation at least had some. "The Sensorites" needs a lot more shaping from Whittaker and Lambert, but it probably looked better on the page and much of the blame has to be placed at the hands of the directors and, to a lesser degree, the actors. "The Sensorites" could probably have been saved by cutting it down to four episodes and increasing the amount of screentime of the Commander and the survivors of the original Earth expedition. As it is, this is probably the weakest story to date and had things gone on like this, it's hard to imagine that the programme would have long survived. Luckily, every story is a reboot for Who. Things can get better.
The best thing on the DVD is Toby Hadoke documentary "Looking for Peter". Peter R. Newman's short life and scant career are a tragedy of unfilled potential. He suffered writer's block and worked as a porter at the Tare Gallery. He died after a fall at the gallery in 1975, aged just 48. He never got to have the consolation though "The Sensorites" isn't very good, he and it aren't and won't be forgotten.
Now Write On...
It is as much, if not more, than the Sensorites could hope for that the RTD created the Ood as an homage to them. The Sensorites are able to remove the TARDIS lock and thus prevent the Doctor and co. getting back in. No other race manage to do that, which suggests either that the Sensorites are a lot more advanced than they look or that the have access to Time Lord(-level) technology that few if any other races in the Whoniverse do. There's a hook there: someone removes the TARDIS lock and the Doctor has to find out where they got the the technology to be able to do that from. It turns out to be the Sensorites. Of course, that just raises another question... I also think there might be some mileage, if handled delicately enough, in the idea of a group all the members of which appear identical to members of the group, but which are clearly differentiable to other people.