The question shouldn't be "is pie chart X better than bar chart Y for making point Z?" but "what is the best way to express point Z?"

In this case, the given bar chart was a poorer way to express the point. Here's a text diagram which I believe is more informative than the give pie chart, though I have some fencepost errors due to character alignment.

    [      A    │  B │ C │D]
   0'     '     '12   '    '24

A variation is:

    AAAAAAAAAAAABBBBBCCCCDDD
   0|     '     ½    '     |1

or if you don't want to count the letters, here's a variation with an explicit count:

          A       B    C  D
    [----12----][-5-][4-][3]
   0|     '     '    '     |24