What Kate said.

Since Execute is 15 rage, and Cleave is 20 rage so it's going to prefer Execute when it is possible.

Whirlwind is going to be a different problem. What you might try is tp have a 2-step mapped key and set "do not progress to the next step" option. 3 seconds pressing the Whirlwind button, then 7 seconds pressing cleave/execute. Or something like that.