Wouldn't that mean that Opportunity Strikes affect Deep Wounds damage in the same way, since they can crit as well? Obviously to a lesser extent, since haste gives more Heroic Strikes.
Also, bleed effects ignore armor, so Deep Wounds damage is not affected by higher CS uptime. However it is affected by stance.
Additional side note: Deep Wounds stacks, though it's hard to tell by looking at your target's debuffs. No damage is lost if you crit again before the current application falls off. Therefore haste/mastery are not devalued from this perspective.
If you were to proc Deep Wounds twice in a very small period of time would that not get into munching?