Holy **it I'm going bananas here!!! 😮
It's cool that it is free, but I hope it would cost something. Just to get hopes up for them to make more!

Yes. The heroes are tired after a full campaign. Let them rest in peace. And get out those freshmen still eager to kill (and get killed).

Elder Mok is so powerful anyway, does he even really need a house ruled heroic feat?

I'm with Charmy on this. But this also comes from my gutt feeling.
As the hero gets recovers health and gets up, he goes like: "Well, I'm supposed to be here now, but this space is occupied. I have to 'move' somewhere else." Hence, Elder Mok will recover health before the hero is 'moved'.
ps. awesome problem Sadgit

What is your opinion with Elder Mok's heroic feat in Road to Legend? It is a pity if it is treated as a blank.
Elder Mok - Heroic Feat:
"Use at the start of your turn to look at the overlord's hand of Overlord cards. The overlord discards 1 card of your choice"
 
Official rule states:
Elder Mok – Heroic Feat: This Heroic Feat has no effect
Source: https://images-cdn.fantasyflightgames.com/filer_public/3c/bb/3cbb5642-39da-41dc-821b-daf729b1f15e/road_to_legend_rules.pdf
 
In a forum house rule idea is:
"Elder Mok’s heroic feat: Use when a monster group activates to treat the Special Effect of that activation as blank."
Source: https://boardgamegeek.com/thread/1574369/road-legend-alternative-hero-options