Urriak Uruk
Gaming is fun, and fun is for everyone
That is my point, these setting are too deep, diverse, and complex with long histories to summarize these Settings into a line or two.
I honestly think it is important to try to distill these settings into a line or two. If you don't, there isn't a great argument as to why to choose one setting or another. After all, FR, Greyhawk, and Mystara have a lot of themes and tropes that overlap, so it is very important to me to find what makes them distinct.
You really think so? What trope is missing from the Forgotten Realms? There is a FR version just about everything you can think of up to and including a FR version of the Mongolian Horde, Great Wall of China, and more. Look long enough and you find everything in FR.
I think FR does circumvent some of the kitchen sink problems by putting differing things in sufficiently far areas of the world (either geographically or figuratively). I think it still has some of those flaws of doing "too much at once," but I think 5e has done a fair job at keeping those elements distinct (although when you read Undermountain you do get a first-hand experience for how bananas everything is when clustered in the same area).