There are 2 big considerations:
1) simplicity of the sensors. Meaning how easy is it to use the output of the sensors to get to a useful model of the situation. Accelerometers, what you'd call "sensors" are somehwat easy (though nowhere near as easy as you'd suspect, read up on kalman filtering for a few of the considerations)
2) comprehensiveness of the sensor information. Meaning if you've got just the output of this sensor, how much do you know (after careful analysis). Accelerometers only give you one aspect, so they fail pretty badly.
Cameras are definitely comprehensive sensors. They are really good to understand afterwards exactly what happened. Not so easy to write control loops against.
The fun thing is that nature has diametrically chosen for comprehensive sensors, coupled to a nervous system that can learn extremely complex feedback loops. Feedback loops so complex that you'd have zero hope of ever modeling correctly in a lifetime. Humans move based on information from one eye (not even 2 eyes, but sometimes the left hemisphere controls the body based on information of the right eye, sometimes the right hemisphere controls based on information of the left eye).
Now if you look at the control tasks that nature can carry out, versus what we can do using technologically, we are pretty pathetic. Bats, for example, fly at 50-60km/h right through the leaves of bushes and trees in pursuit of insects in total darkness (using sonar) without impacting any of the branches, they locate insects on the other sides of branches or leaves without even looking, and they do this with thousands of interfering signals sent out by independant mobile platforms [1]. They can fly through a bush as if it's not even there.
The limit of human technology when it comes to sonar are ultrasonic distance sensors [2] ... there's no comparison.
So yes, technology uses sensors, but we really shouldn't. It's not getting us anywhere, at least not in mobile robotics, like rockets. Trouble is, it's such a very very hard problem.
[1] https://www.youtube.com/watch?v=sisyq6N7mMw#1:51 [2] https://www.youtube.com/watch?v=_xtJL3AXf5o
http://www.forbes.com/sites/alexknapp/2014/04/25/spacex-falc...
The above article says the next landing zone will be closer to land which should increase the chances of a successful recovery.