The problem with photography discussions is everything works together and digital just makes the everything more complicated.
There are major differences in the complicated stuff that produces the image, but not in the end result for most photography.
Checked out the moments of math tutorial. Here's a number to add to it. My phone camera has a 1/3.2" sensor with roughly 500,000 pixels per square millimeter. That's more pixels in a square millimeter then the first digital sensors had total. I need to experiment some more, but it seems to handle low light better than the D3200. Now the whole package of the camera phone can't compete with a DSLR.
Point is the technology is passed the point of sensor size meaning much of anything and they are only going to get better.
Still might need an FX or MF or 8x10 for some other reason, but it's not really going to be the sensor if looking at newer cameras.