Comment by nacs

> Writing the above equation in JSON would be just as terrible

Not quite as bad as XML.. I think the problem is more the verbose, overly-nested format that was chosen for MathML than XML itself though.

  {
    "mrow": {
      "mi": [ "x", "=" ],
      "mfrac": {
        "mrow": {
          "mi": [ "−", "b", "±" ],
          "msqrt": {
            "mrow": {
              "msup": {
                "mi": [ "b", "2" ]
              },
              "mi": [ "−", "4ac" ]
            }
          }
        },
        "mi": "2a"
      }
    }
  }