I would never use cheese while playing, recipe for disaster.

Great idea but it would totally break my immersion:)

I do not see that anything in Descent is "broken". It's a perfectly fine game in my opinion. Sure, there are heroes and classes that are stronger than others. There are also OL cards and plot decks that are stronger than others. And of course there are players that are more experienced, more competitive or generally better in these kinds of games. However, if playing with sensible people whose primary goal is to have fun during a campaign, you can  adjust for any imbalances that might occur with just the components that are available.

Hmm minus range could still work within melee, but then it at least needs to be -3 or -4 range to have any effect. Much like the stealthy monster passive skill.
There are already a few surge requiring mechanics out there, but I am not a big fan of it. Perhaps something more like the Nightstalker ability of the Master Barghest, or just a passive defense bonus.