I haven't seen the figures since the most recent batch of changes, however you will find that the reason it isn't used without a bloodsurge proc is based on the DPR (Damage per Rage) from memory Wild Strike is quite expensive, so using it without the proc will mean there is less rage left for other abilities (like HS).
As said thousands of times before, you should not compare HS and WS. Even though they are both damage dealing abilities, HS is off GCD, making it relying on only but only rage whereas WS relies on both rage and GCD.
Right time to use WS is when you don't have BT, RB or Berserker Rage+RB. There are lots of times that we don't get an enrage proc or berserker rage to activate RB, leaving us only with BT and WS. Keeping BT on cooldown, all the remaining GCDs go to WS untill you get an enrage proc to be able to use RB. If you have even more rage then HS at any moment. (of course, talking about above 20%)
WS does more damage then HS and WW, what is the reason to not use it when there's no bloodsurge?
It starts the global cool-down, while Heroic Strike does not.
If you delay Raging Blow or Bloodthirst by using normal Wild-strike and starting the global cool-down you have lost DPS from Raging Blow/Bloodthirst.
If you are sure using Wild Strike will not delay the use of Bloodthirst or Raging Blow, use it instead of Heroic Strike.