First, I need to say that I loooove the concept of Heroes (here and in ES2), it really makes me want to play the game again and again, collecting them like various Pokemon. And because of that I really want Heroes to have some little special innates in battle. Yes, I can get certain Heroes, because they are good Councilors. Yes, I can get Heroes of certain fighting roles, as their Race+Class has the thing I need. But I also wish I had an opportunity to care when choosing between two Heroes that are the same.
Neither of the bow and arrow Necros are gonna sit in Council for me this game, but I looove to battle in this game. So the only distinguishing factor left is that Speaks-In-Riddles being a more funny name than Among-The-Dead, thus they win. That feels like a (totally understandable but still) a missed opportunity. And no, the attribute system isn't good enough at the moment, as the spreads aren't too crazy (see the screenshot for example). A slightly crazier spread might work as a specialty thing (more determination - a procaster, more might - a rightclicker).
I only have ES2 experience as a point of comparison, so I'll draw from there. Heroes there had a fighting and a governing innate, that gave them a slight edge over one another. Some had more offensive power, some more defensive, and some more FIDSI boosts. Yet there still were such cases as this one in the screenshot, however I always had a thought process behind picking one or another instead of just winging it (a flat bonus guy for early game or a scaling bonus guy in the late game for example).
I could see this being implemented in little things, such as "+dmg to melee units", "+def to minors". Or it could be a bit more substantial like "+% dmg per each allied hero in battle", "makes debuffs last longer", "has a vulnerability aura to deduct a small def%", so that it mimics a regular ability in a way.