Look at this:
What do you think?
Darn, to be honest I'm really questioning the decision to make Grima a hero... But I guess it's still pretty valid. The thing is that while I get Grima wasn't always evil is because in the books ever since we meet him he's evil so it makes me think that Tolkien makes this character evil in his very nature aand thus making the idea a bit too fan-fiction-ish, but I guess if you stretch the imagination is possible. Either way thematically, he's actually a pretty good hero! Reducing the cost of pretty cheap events is great, but it's still and action and not a response, still, it's lore so he works great with Strider.
Now that I think of it, you could interpret the Grima thing in a completely different way, and think it like a new "faction" in the game, like when in Meccg you could play as a fallen wizard, those were the kind of "heroes" you could use, so it kiiiinda could be comparable to that.