Orcs don't have darkvision, but their heroes do.
Undead and Dwarves don't have darkvision.

What do people think of this? Personally I think Orc heroes should lose darkvision, and the undead and dwarves should gain it.

I've always thought Dwarves should have Darkvision, especially since they tend to dwell in mountains and stuff. Orcs aren't really an underground race in this game, so they're fine without it.

Undead...eh? Could go either way. I think they don't really need it. Maybe put it on a select few units, like the Reaper.

Dwarves should definitely have it given how they're an underground race in the official campaign. Neither the UD race or Orc heroes need it in my opinion.

Hmmm.. yes but Dwarves do have mountaineering and cave crawling which can both be a great advantage based on the map. I am looking this from balancing angle when compared to Goblins (who are definitely underground race), should their units be given poison immunity or something else to compensate then perhaps?

If it's only question of opinion, yes Dwarves should maybe have it, but Undead and Orcs don't need it.

If you're looking at it in terms of accuracy, I would say it would make sense that Dwarves could have darkvision. In terms of balance.... they already have cave crawling and mountaineering, I don't think they also need darkvision whereas their counterpart, the Goblins, don't have mountaineering and tend to be a tad weaker in terms of health and survivability. So balance-wise it makes sense that the Goblins would have it and the Dwarves would not.

It makes the Moles even more valuable as underground scouts.