You are assuming the tape you put over the camera is not transparent at IR or UV light frequencies - think of the Sony 'night-vision' cameras that could see through clothes.
You are also assuming the gain of the microphone can't be turned up remotely to hear enough. Some decent signal processing can remove a lot of the underlying noise to recover the what is being said.
Ask yourself too, how many owners are going to keep the TV firmware updated to deal with the inevitable security holes that will be found?
Personally, I think it's not paranoid at all to question the pros and cons of these new 'features', inevitable as they may be.