Due to how haste effects stack wouldn't it be optimal to pop a Potion of Speed during heroism?
Edit: This time with math.
We'll assume 0 haste on gear and Windfury totem/Improved Icy Touch. In 1 minute without a potion or heroism you will get 72 auto-attacks. If you start with heroism for 40 seconds and then pop a Potion of Speed for the next 15 seconds, you will get
If you pop Potion of Speed with Heroism you get
Edit #2: The math is trivial so I'm not going to bother including it, but haste on gear has no effect on this outcome, so in order to maximize your attacks you should always stack Potion of Speed with heroism. This doesn't necessarily make this strategy better than popping it during a trinket proc.