I`d say it would get to complex. The single class abilities will give way to much keybinds. For me a DK was to much allready so I went to 5rets.

You can click most of the standard dps abilities in a click macro but there is stuff like the DK`s control abilities and shamans wolfs, warrior charge and such things. Those need a LOT of keybinds.

+ the speed difference, warrior charges, persuit of justice on the pallies.