Some think that the number of pixels defines sensor technology. That's why we had megapixel wars, because the uneducated masses think that more is always better.
Besides pixel count there is dynamic range and color sensitivity. Higher pixel count while keeping the noise levels down is a net plus. You can always reduce pixel count in software but you cannot increase it.
However, MP count does not define technology, and it creates issues for many users who do not own or want to own the fastest and latest computers. My D800 low light images took way to long to render in LR 4 on my fairly new computer, and NR or brush actions took a almost unbearable amount of time. I used it for a couple low light events, and processing 500 images took far too much time, so I sold it. The 5D MK III images process very quickly. I also found that even with high end Nikon glass, I usually could not take advantage of all those pixels. The best images were definitely better, but in the end, it wasn't worth the time to process them.
I could see a landscape photographer who took a few images and had time to process them being very happy with a high mp camera, but not the average Rebel user.
Of course, there will always be those who brag about how many MP their camera has, but only a few who can take advantage and actually get more detail. In any event, a user will not get worse images, that's not a concern.
Well that's what I call an educated opinion - rarely found around here in the heat of the discussion.
What i'd like to see is an sensor with a pixel resolution much beyond the diffraction limit (i.e. about 16 times the megapixels we have now) which makes antialiasing filters and demosaicing virtually redundant. From this sensor we can downsample by a factor of 2 to 10 in order to get processable and sharp images without the problems at pixel-level we have today. I'm sure this will happen within 5-15 years but i'm not sure if canon or nikon are the first to introduce this technology. Maybe canon has development started on something like this because while it won't perform very well in the high-iso-regime it will surely blow minds in the low-iso-regime (ISO25).