Would it be a significant indicator (of anything) if we had a graph showing the change in the 50% rating value?
You can see the momentary value on the Rating Distribution graph. It's 1513 at present, and exactly the rating of the 35th ranked player (Facetroll, atm).
Yeah. I think it would be an interesting data point to see how the median rating trends over time on MDL. If we add a chart for number of players over time as well, it would help us see the effect of that on ratings.